CN102469545A - Method and device for planning itinerary of mobile agent - Google Patents

Abstract

The invention discloses a method and a device for planning the itinerary of a mobile agent, which relates to the technical field of wireless sensor network, reduces the energy consumption of the WSN (Wireless Sensor Network) network and prolongs the service life of the WSN network. The method comprises the following steps: if the accumulated value of the information gain is not larger than the threshold value of the information gain, determining the candidate position of a target object at the next time; judging whether the distance between the position of the node of the host sensor in which the mobile agent is located at present and the candidate position is larger than a first threshold value; if the distance is not larger than the first threshold value, un-moving the mobile agent; and if the distance is larger than the first threshold value, selecting the node of a target sensor from the nodes of the neighbors sensors of the host sensor in which the mobile agent is located, and moving the mobile agent to the node of the target sensor. The embodiment of the invention is mainly applied to the process of planning the itinerary of the mobile agent in target tracking scenes.

Description

Mobile agent stroke planning method and device

Technical field

The present invention relates to wireless technical field, relate in particular to a kind of mobile agent stroke planning method and device.

Background technology

WSN (Wireless Sensor Networks, wireless sensor network) is made up of a large amount of sensor nodes that are distributed in the certain space scope.This sensor node can be to the destination object in its overlay area (for example; Vehicle; Mobile phone terminal, even object movably such as animal) carry out signals collecting, and carry out data communication with other sensor nodes; Thereby obtain the information of this destination object, realize the location and the tracking of destination object.

At present, when location of realizing destination object and tracking, can adopt a kind of computational methods that the information that sensor node collects is handled based on mobile agent.This mobile agent can be selected place of operation and time voluntarily, interrupts current self execution as the case may be, when moving to another sensor node, can resume operation and correlated results in time returned.Generally, mobile agent has four kinds of attributes: sign, stroke planning, data space and method.Wherein, stroke planning can be confirmed the source node set of mobile agent visit and the order of access node.

Prior art adopts a kind of PDMAI (Predictive Dynamic Mobile Agent Itinerary, the dynamic mobile agent stroke planning of predictability) method to realize the stroke planning of mobile agent.This method mainly comprises following three steps:

The first step: the sensor node that will at first detect destination object is as processing center, and on this sensor node, creates mobile agent.The beacon message of the neighbours' sensor node that receives according to this sensor node; Utilize information and its two beacon messages that receive at first of mobile agent place host's node (sensor node at the current place of mobile agent); Mobile agent can calculate the position of above-mentioned destination object through three limit location algorithms, calculates the information gain I of host's node then ₀And initialization Carry=I ₀, then determine neighbours' sensor node that above-mentioned mobile agent needs are moved to according to the next-hop node selection criterion.

Second step: mobile agent is moved to neighbours' sensor node of decision, and the sensor node that move to this moment is host's node.At this moment, can calculate the position x of destination object through three limit location algorithms ^Λ(t), calculate the information gain I of host's node then _k, and upgrade Carry=Carry+I _kIf Carry then carried out for the 3rd step greater than the horizontal Desire of the information gain of predesignating, otherwise continue to determine neighbours' sensor node that its needs are moved to, then return and carried out for second step according to the next-hop node selection criterion.

The 3rd step: mobile agent returns processing center.

Yet; Adopting above-mentioned PDMAI method to realize in the process of mobile agent stroke planning; The phenomenon that is moved easily and frequently moves between the several sensors node of agency in certain zone; Cause the energy consumption of WSN network to increase greatly, the useful life of also having reduced the WSN network simultaneously.

Summary of the invention

Embodiments of the invention provide a kind of mobile agent stroke planning method and device, reduce the energy consumption of WSN network, prolong the useful life of WSN network.

Embodiments of the invention adopt following technical scheme:

A kind of mobile agent stroke planning method comprises:

If the accumulated value of information gain is not more than the information gain threshold value, confirm the position candidate of destination object in the next moment;

Whether position and the distance between the said position candidate of host's sensor node of judging the current place of mobile agent be greater than presetting first threshold;

If said distance is not more than said first threshold, do not move said mobile agent; If said distance is greater than said first threshold, select target sensor node from neighbours' sensor node of host's sensor node at the current place of said mobile agent is moved to said objective sensor node with said mobile agent.

A kind of communicator comprises:

Confirm the unit, be used for confirming the position candidate of destination object in the next moment if the accumulated value of information gain is not more than the information gain threshold value;

Judging unit, whether position and the distance between the said position candidate of host's sensor node that is used to judge the current place of mobile agent be greater than first threshold;

First migration units is used for not moving said mobile agent if said distance is not more than said first threshold; If said distance is greater than said first threshold, select target sensor node from neighbours' sensor node of host's sensor node at the current place of said mobile agent is moved to said objective sensor node with said mobile agent.

By the described embodiment of the invention of technique scheme; When if the position of host's sensor node at the current place of mobile agent and the distance of destination object between the position candidate in the next moment are not more than said first threshold; Said mobile agent is not moved, thereby can reduce the number of times that mobile agent moves, especially; When the movement velocity of destination object is slow; Can overcome the problem that mobile agent frequently moves in the prior art, thereby reduce the energy consumption of WSN network, prolong the useful life of WSN network.

Description of drawings

In order to be illustrated more clearly in the embodiment of the invention or technical scheme of the prior art; To do to introduce simply to the accompanying drawing of required use in embodiment or the description of the Prior Art below; Obviously, the accompanying drawing in describing below only is some embodiments of the present invention, for those of ordinary skills; Under the prerequisite of not paying creative work, can also obtain other accompanying drawing according to these accompanying drawings.

The flow chart of a kind of mobile agent stroke planning method that Fig. 1 provides for the embodiment of the invention;

The flow chart of the another kind of mobile agent stroke planning method that Fig. 2 provides for the embodiment of the invention;

First kind of the emulation experiment that Fig. 3 provides for embodiment of the invention sketch map as a result;

Second kind of the emulation experiment that Fig. 4 provides for embodiment of the invention sketch map as a result;

The third of the emulation experiment that Fig. 5 provides for the embodiment of the invention be sketch map as a result;

The 4th kind of the emulation experiment that Fig. 6 provides for embodiment of the invention sketch map as a result;

The structural representation of a kind of communicator that Fig. 7 provides for the embodiment of the invention;

The structural representation of the another kind of communicator that Fig. 8 provides for the embodiment of the invention;

The structural representation of another communicator that Fig. 9 provides for the embodiment of the invention;

The structural representation of another communicator that Figure 10 provides for the embodiment of the invention.

Embodiment

To combine the accompanying drawing in the embodiment of the invention below, the technical scheme in the embodiment of the invention is carried out clear, intactly description, obviously, described embodiment only is the present invention's part embodiment, rather than whole embodiment.Based on the embodiment among the present invention, those of ordinary skills are not making the every other embodiment that is obtained under the creative work prerequisite, all belong to the scope of the present invention's protection.

Embodiment as shown in Figure 1 provides a kind of mobile agent stroke planning method; Wireless sensor network satisfies following condition in the present embodiment: sensor node is laid on the two dimensional surface; The location aware of each sensor node; Each sensor node has two neighbours' sensor nodes at least, and all the sensors node all is calibration and time synchronized, and the movement velocity of destination object and direction can not suddenlyd change.This method comprises:

101, if the accumulated value of information gain is not more than the information gain threshold value, host's sensor node at the current place of mobile agent is confirmed the position candidate of destination object in the next moment.

Optional, said destination object can be confirmed according to the historical position and the current location of destination object in the position candidate in the next moment.The historical position of said destination object can comprise the position of said destination object in a plurality of historical junctures; When the historical position of destination object is the position of said destination object in the last moment; Can obtain the position of said destination object, for example can calculate destination object in each position constantly through three limit location algorithms at current time.If the speed of service of said destination object and direction can not undergone mutation in the certain hour scope, the difference of then said destination object between the position in adjacent two moment can not suddenlyd change yet.Thereby; A kind of historical position according to destination object confirms that said destination object in the method for the position candidate in the next moment is: x ' (t+1)=x (t)+(x (t)-x (t-1)); Wherein, X ' (t+1) representes said destination object in the position candidate in the next moment, and the said destination object of x (t) expression is in the position of current time, and the said destination object of x (t-1) expression is in the position in the last moment.

Whether position and the distance between the said position candidate of host's sensor node of 102, judging the current place of mobile agent be greater than first threshold.

This first threshold can be confirmed according to the communication distance of host's sensor node at the current place of said mobile agent.When using, for example this first threshold can be set to the special ratios of host's sensor node communication distance, and even said host's sensor node communication distance is L, and then this first threshold can be L*k, 0＜k＜1.Preferably, in order to ensure the probability of the correct perception destination object of host's sensor node better, and can not cause mobile agent frequently to switch; When first threshold is L*k; K does not choose too the value near 0 or 1, and for example the value of k can be for 0.5≤k≤0.8, at this; The value of k is merely a kind of implementation method in the embodiment of the invention, is not restricted to this.

103, if said distance is not more than said first threshold, do not move said mobile agent; If said distance is greater than said first threshold, from neighbours' sensor node of host's sensor node at the current place of said mobile agent, select the objective sensor node of mobile agent migration, said mobile agent is moved on the said objective sensor node.

By the described embodiment of the invention of technique scheme; When if the position of host's sensor node at the current place of mobile agent and the distance of destination object between the position candidate in the next moment are not more than said first threshold; Said mobile agent does not move, thereby can reduce the number of times that mobile agent moves, especially; When the movement velocity of destination object is slow; Can overcome the problem that mobile agent frequently moves in the prior art, thereby reduce the energy consumption of WSN network, prolong the useful life of WSN network.

In the prior art, when needing the objective sensor node of migration for the mobile agent selection, definition t moment mobile agent is from sensor node S _kMove to objective sensor node S _jCost function C _Kj(t) as follows:

$C_{\mathrm{kj}}\left(t\right)=a\·\frac{E_{\mathrm{kj}}}{E_{\max }}+b\·(1-\frac{I_j\left(t\right)}{I_{\max }})+(1-a-b)\·(1-\frac{e_j\left(t\right)}{e_{\max }})$

Wherein, E _KjExpression with mobile agent from sensor node S _kSend to sensor node S _jThe energy that consumes, e _j(t) be sensor node j in t energy remaining constantly, correspondingly, E _MaxIt is the ceiling capacity that mobile agent consumes when between two sensor nodes, moving.I _MaxBe the maximum information gain that sensor node can provide, I _j(t) be the information gain that sensor node j can provide, e _MaxIt is the initial energy value of sensor node.A, b are significance level and the 0≤a that weight coefficient is used to adjust these three parts, b≤1.By above-mentioned cost function C _KjThe selection criterion of next the jump set sensor node that (t) obtains is:

$j^{*}=\arg \underset{j\∈N_k}{\min }[a\·\frac{{\left|\right|x_k-x_j\left|\right|}^2}{d_{\max }^2}+b\·\frac{{\left|\right|x^{\mathrm{\Λ}}(t+1)-x_j\left|\right|}^2}{{\mathrm{ds}}_{\max }^2}+(1-a-b)\·(1-\frac{e_j\left(t\right)}{e_{\max }})]$

Wherein, N _kBe the set of neighbours' sensor node of sensor node k, j ^*∈ N _kBe next jump set sensor node that mobile agent will be moved to, d _MaxBe the maximum communication distance of sensor node, || x ^Λ(t+1)-x _j|| be that sensor node j is to the distance of destination object in the position in the next moment, ds _MaxIt is the maximum perceived distance of sensor node.

Owing in cost function, introduced mobile agent from node S in the prior art _kSend to node S _jThe energy that consumes makes computation complexity higher.Though the transmitting power of sensor node can be adjusted according to transmission range, in fact can not adjust the energy that transmitting power can be wasted node on the contrary continually in real time according to the dynamic change realization of network.

In embodiments of the present invention, mobile agent from host's sensor node at current place move to objective sensor node cost function can for: Wherein, e _j(t) be that node j exists) t moment energy remaining, e _MaxBe the initial energy value of sensor node, I _j(t) be the information gain that sensor node j can provide, I _MaxIt is the maximum information gain that sensor node can provide.Weight coefficient a is used to adjust the significance level and 0≤a≤1 of these two parts.The selection criterion of the objective sensor node that the cost function that provides according to the embodiment of the invention draws (being next jump set sensor node) is expressed as: $j^{*}=\mathrm{Arg}\underset{j\∈N_k}{\mathrm{Max}}[a\·\frac{e_j\left(t\right)}{e_{\mathrm{Max}}}+(1-a)\·\frac{I_j\left(t\right)}{I_{\mathrm{Max}}}].$

The cost function that the embodiment of the invention provides has overcome prior art need be to mobile agent from node S _kSend to node S _jThe energy that consumes calculates, and causes the computation complexity problem of higher, has reduced the energy consumption of sensor node, and then has reduced the energy consumption of WSN network.

For the implementation procedure of more complete description mobile agent stroke planning method, will realize that the whole process of migration describes in detail from the mobile agent that is created to of mobile agent below, as shown in Figure 2, comprising:

201,, create mobile agent at initial time.

For example, can be with first initial sensor node that detects destination object as processing center, and on said initial sensor node, create mobile agent.This initial sensor node is host's sensor node at the current place of said mobile agent.

202, receive the beacon message of neighbours' sensor node transmission of said initial sensor node.

Said beacon message can comprise position, dump energy, measured value and the beacon rise time of sensor node.

Need to prove, in the application scenarios that the embodiment of the invention provides, can use beacon frame to carry out periodic information exchange between the adjacent sensor node.Said beacon frame carries above-mentioned beacon message.The form of said beacon frame is as shown in table 1 below,

The position x of sensor node k

Dump energy e k(t)

Measured value z k(t)

Beacon rise time t

The beacon message that carries in table 1 beacon frame

Wherein, x _kThe position of expression sensor node k can use the x coordinate of sensor node k and y coordinate information to represent dump energy e _k(t) be the remaining electric energy of sensor node; If sensor node adopts acoustics amplitude transducer, sensor node k can be expressed as at the measured value of beacon rise time

E is that (this signal energy is relevant with sensor type for the signal energy of destination object radiation; When sensor node adopts acoustics amplitude transducer; E representes the acoustic wave energy of destination object radiation), x (t) is a destination object in beacon rise time t position constantly, || x (t)-x _k|| be sensor node k and the destination object Euclidean distance between beacon rise time t position constantly.

Need to prove that also in embodiments of the present invention, the operation of host's sensor node at mobile agent place can be based on fixed time period T, each cycle is divided into two parts: beacon frame receives stage and mobile agent stroke planning stage.Receive the stage at beacon frame, host's sensor node does not send beacon message, receives only the beacon message of its neighbours' sensor node and stores; In the mobile agent stroke planning stage; The operation of the beacon message decision that receives before the beacon message that mobile agent utilizes host's sensor node self and this host's sensor node its next step, the beacon message that this moment, host's sensor node neither sent self does not receive the beacon message of its neighbours' sensor node yet.

203, the beacon message that sends according to neighbours' sensor node of the beacon message of said initial sensor node and said initial sensor node; Choose first three maximum sensor node of measured value in all beacon messages; According to the position that the beacon message of said three sensor nodes obtains the current time of destination object, note is made primary importance.

For example, three limit location algorithms be can adopt, first three maximum sensor node of above-mentioned the measured value position of the sensor node in the beacon message and the current primary importance that measured value obtains said destination object separately utilized.Concrete computational process can repeat no more at this with reference to present technology.

204, obtain the information gain of the sensor node of measured value maximum in said three sensor nodes, note is done first information gain.

For example, can use the Gaussian distribution of zero-mean that information gain is carried out modeling and draw following formula:

Wherein, I _kThe expression information gain of sensor node k when moment t, σ representes standard variance, I when σ has determined that distance increases between destination object and the sensor node _kThe quick degree that reduces, x ^Λ(t) be the position of the destination object that calculates according to three limit location algorithms.

Optional, obtain first information gain according to

.

Need to prove; Host's sensor node at the current place of said mobile agent is preserved the above-mentioned primary importance that gets access to; Gain is accumulated to the first information; In the moment in the future, said primary importance will participate in as the historical position of destination object in the computational process of position candidate of destination object.

205, utilize the current primary importance of said destination object from neighbours' sensor node of said initial sensor node, to select first objective sensor node, said mobile agent is moved to said first objective sensor node.

For example, can basis

From neighbours' sensor node of said initial sensor node, select first objective sensor node; This formula is the next-hop node selection criterion that provides according to the embodiment of the invention Making amendment draws, wherein, and j ^*Represent first objective sensor node, and j ^*∈ N _k, 0≤a≤1, N _kRepresent the set of neighbours' sensor node of said initial sensor node k, e _j(0) is illustrated in the dump energy (electric energy) of the first sensor node j that constantly receive, e _MaxThe initial energy value (electric energy) of expression sensor node, x ^Λ(0) represent said primary importance, || x ^Λ(0)-x _j|| the position of expression sensor node j is to the distance of said primary importance, ds _MaxThe maximum perceived distance of expression sensor node.

According to the next-hop node selection criterion Make amendment and draw

Process following: since between host's sensor node at information gain and the current place of mobile agent and the destination object apart from becoming opposite relation; Promptly distance is more little; Information gain is big more; Simultaneously dump energy also is opposite relation with the energy of consumption, therefore makes the node of dump energy and information gain sum maximum, promptly is equivalent to make consumed energy (e _Max-e _j(0)) node minimum and between mobile agent host node and the destination object apart from sum.The appearance of square distance is in information gain modeling

formula, and gain is the inverse relationship that square becomes with distance.

In the prior art, mobile agent can utilize current place sensor node and the beacon message that receives at first positions destination object, and the position possible error that obtain destination object this moment is bigger.Because the channel competition between the sensor node can make what the beacon message that receives at first was not necessarily to send from the nearest sensor node of destination object.And under the normal condition, those sensor nodes that signal strength signal intensity is bigger are normally nearer from destination object.Thereby; When the embodiment of the invention is carried out the location of destination object in above-mentioned steps 203; The beacon message of maximum first three sensor node of measured value calculates the primary importance of said destination object in first moment in the beacon message that utilizes said initial sensor node and the beacon message of its neighbours' sensor node; The accuracy of destination object location can be improved, and then the reliability of mobile agent when moving judgement can be improved.

In addition; Need to prove that what above-mentioned 201-205 described is at initial time, sensor node is created mobile agent; And mobile agent moved to next jump set sensor node, the process of promptly said first objective sensor node from initial host's sensor node.Because mobile agent does not have the historical position of destination object when the initial time of setting up; Thereby also unpredictablely go out the position candidate of destination object in the next moment; So in the present embodiment; Mobile agent when initial host's sensor node is moved to next jump set sensor node, can not moved according to the position of initial host's sensor node and next position candidate of destination object, and can directly move.

After mobile agent is moved to current sensor node from last sensor node, will move according to following method:

206, host's sensor node at the current place of mobile agent receives the beacon message of neighbours' sensor node of host's sensor node at the current place of said mobile agent.

207, host's sensor node at the current place of mobile agent is chosen first three maximum sensor node of measured value in all beacon messages according to the beacon message in neighbours' sensor node of the beacon message of host's sensor node at the current place of said mobile agent and said host's sensor node; Obtain the position of said destination object at current time according to said three sensor nodes beacon message separately, note is made the second place;

The measured value that comprises in can beacon message according to host's sensor node at the current place of said mobile agent; With the measured value that comprises in the beacon message in the neighbours' sensor node that receives; Compare and measure value, and choose first three maximum measured value corresponding sensor node.Beacon message according to these three sensor nodes obtains the position of destination object at current time then, for example, can utilize three limit location algorithms to calculate said destination object in the current second place.

Need to prove that the said second place also will be preserved, in the next moment, the said second place will participate in as the historical position of destination object in the computational process of the position candidate of confirming destination object.

208, obtain the information gain of the sensor node of measured value maximum in said three sensor nodes, note is made second information gain, and said second information gain is accumulated.

Whether the accumulated value of 209, judging said information gain is greater than the information gain threshold value that is provided with.

The accumulated value of said information gain be mobile agent before the accumulated value of the information gain that obtains on each host's sensor node of moving to; This information gain is the information gain that a maximum sensor node of the measured value in neighbours' sensor node of host's sensor node can provide for destination object, and this information gain can be used for representing that sensor node is for the percentage contribution of knowing destination object information.

Need to prove that the information gain threshold value is to require to set according to concrete application scenarios, has reflected the precision to target following; Generally speaking; Along with the migration of mobile agent, the information of the target that gets access to is constantly increasing, and the accuracy of tracking is also in continuous improve; When the requirement that reaches appointment; The velocity error that is not more than 1 meter or target such as position error is not more than 1 meter error with direction and waits (can think when information gain reaches 30-50 that the requirement of above-mentioned appointment just can be satisfied this moment) less than 60 degree, promptly thinks to have reached the information gain threshold value.

Said information gain is a nondimensional amount, the certain amount of information of target contribution that each migration of mobile agent is all followed the tracks of needs, and this amount of information is information gain, adopts Gaussian distribution to carry out modeling to information gain in the present embodiment, can not have unit.

210, when the accumulated value of said information gain during greater than the information gain threshold value that is provided with, mobile agent returns processing center.

211, when the accumulated value of said information gain is not more than the information gain threshold value of setting, confirm the position candidate of said destination object in the next moment according to the historical position of destination object.

Optional, when the historical position of destination object is the position of said destination object in the last moment, at first obtain the position of said destination object at current time, for example can calculate destination object in each position constantly through three limit location algorithms.If the speed of service of said destination object and direction can not undergone mutation in the certain hour scope, the difference of then said destination object between the position in adjacent two moment can not suddenlyd change yet.Thereby; Can according to the historical position of destination object confirm the position candidate of said destination object in the next moment: x ' (t+1)=x (t)+(x (t)-x (t-1)); Wherein, X ' (t+1) representes said destination object in the position candidate in the next moment, and the said destination object of x (t) expression is in current location, the position in the last moment of the said destination object of x (t-1) expression.

Whether position and the distance between the said position candidate of host's sensor node of 212, judging the current place of mobile agent be greater than first threshold.

213, when said distance is not more than said first threshold, do not move said mobile agent.

If host's sensor node at the current place of mobile agent does not move this mobile agent, moment under connecing then, can repeated execution of steps 207, and current time t is updated to t+1.

214, in said distance during greater than said first threshold; From neighbours' sensor node of said host's sensor node, select next jumping objective sensor node of mobile agent migration according to utilizing said position candidate; Note is made second objective sensor node, and said mobile agent is moved to said second objective sensor node.

For example, can from neighbours' sensor node of said host's sensor node, select second objective sensor node according to

; The selection criterion of next jump set sensor node that this formula provides according to the embodiment of the invention is made amendment and is drawn.Wherein, j ^*Represent second objective sensor node, and j ^*∈ N _k, 0≤a≤1, N _kRepresent the set of neighbours' sensor node of said host's sensor node k, e _j(t) expression sensor node j is at the dump energy of beacon rise time, e _MaxThe initial energy value of expression sensor node, x ^Λ(t+1) the said destination object of expression is in the position candidate in the next moment, || x ^Λ(t+1)-x _j|| expression sensor node j is to the distance of said position candidate, ds _MaxThe maximum perceived distance of expression sensor node.

In embodiments of the present invention, preferably, the situation that does not satisfy transition condition for fear of mobile agent all the time takes place, and a counter can be set, and the number of times that mobile agent does not move is counted.For example when mobile agent not being moved; This counter increases preset value; When the value of counter during greater than second threshold value; Even judge destination object in the distance of the position in the next moment and host's node still less than above-mentioned first threshold values; Also must reselect new objective sensor node (concrete implementation procedure identical), mobile agent is moved on this new objective sensor node, thereby can avoid single-sensor node short time internal consumption significant amount of energy and cause the unbalanced problem of offered load with the choosing method of above-mentioned second objective sensor node.Need to prove that said second threshold value can be confirmed according to the execution cycle of location computing in the movement velocity and 208 of the communication distance of host's sensor node at mobile agent place, destination object.When the communication distance of host's sensor node at for example said mobile agent place was 50 meters, the movement velocity of destination object was 2 meter per seconds, and the execution cycle of location computing is 10 seconds in 208, then can said second threshold value be set to 3 or 4 times.In step 213, each when confirming not move said mobile agent, can the value of particular count device be increased by 1.Afterwards, if the value that determines said particular count device, is selected next jumping objective sensor node of migration mobile agent greater than 4 o'clock from neighbours' sensor node of said host's sensor node.

In order to prove the validity of the mobile agent stroke planning method that the embodiment of the invention provides, adopt the Matlab emulation experiment to verify parameter setting in the simulated environment such as following table 2 below.

Parameter setting in table 2 simulated environment

In the emulation experiment, the energy consumption of WSN network comprises following a few part: sensor node periodically sends the energy consumption E with received beacon frame _b, the transmission energy consumption E of mobile agent from sensor node k to sensor node j _Kj, neighbours' sensor node of sensor node k receives the energy consumption E of mobile agent _rWith the data processing energy consumption E on the sensor node k _kNetwork life adopts network design to be accomplished to the time of the dead experience of first node in this emulation experiment.

Consume the variation of simultaneous adaptation destination object speed for conserve energy; The communication distance of sensor node is set to adjustable; But adjustable counting is less, has so just avoided sensor node to adjust transmitting power continually, and communication distance adjustable in the emulation experiment is taken as d1=12 respectively; D2=36, d3=60.Simulation result such as Fig. 3-shown in Figure 6.

Fig. 3 is for when the speed v of destination object=10, and the first different threshold values is to the sketch map that influences of network energy consumption.Can find out when adopting prior art (referring to the represented curve of PDMAI among Fig. 4); The network energy consumption does not change with the change of said first threshold values, when the ratio f of first threshold values and maximum communication distance greater than 0.4 the time, along with the increase of first threshold values; When adopting the method (referring to the represented curve of RB-PDMAI among Fig. 4) that the embodiment of the invention provides; The energy consumption of network constantly reduces, but because first threshold values is crossed conference tracking accuracy is descended, so f can choose between 0.5-0.6.

Fig. 4 is for to work as f=0.6, simulation time T=500s, and different speed is to the sketch map that influences of network energy consumption.The speed of destination object is between 10-20 the time; The energy consumption of the method that the embodiment of the invention provides (referring to the represented curve of RB-PDMAI among Fig. 5) obviously is less than prior art (referring to the represented curve of PDMAI among Fig. 5); The method that the embodiment of the invention provides in other velocity intervals simultaneously and the energy consumption of prior art are similar, and only performance is poor slightly in limited velocity interval 4-7.

Fig. 5 is for to work as f=0.6, and when the speed of destination object changed between 2-30, during all the sensors node primary power E=6, the method that adopts the prior art and the embodiment of the invention to provide drew the contrast sketch map of network life.When the speed of destination object is between 10-20; The network life that the method (referring to the represented curve of RB-PDMAI among Fig. 6) that adopts the embodiment of the invention to provide obtains is obviously greater than the network life that adopts prior art (referring to the represented curve of PDMAI among Fig. 6) to draw, and the method that in other velocity intervals, adopts the embodiment of the invention to provide simultaneously is suitable with the network life that adopts prior art to draw.

Fig. 6 is for working as f=0.6; When the speed of destination object changes between 2-30; The method that adopts the prior art and the embodiment of the invention to provide reaches the same time that information gain experienced; It is in most cases basic identical to find out that by Fig. 7 two kinds of methods reach time of identical information gain experience; Therefore compare with prior art (referring to the represented curve of PDMAI among Fig. 6), the method that the embodiment of the invention provides (referring to the represented curve of RB-PDMAI among Fig. 6) does not reduce the precision of following the tracks of.

In sum, through reasonably choosing first threshold values, the method that the embodiment of the invention provides has reduced the energy consumption of the whole network under the prerequisite of guarantee information gain, prolonged network life simultaneously.

Embodiment as shown in Figure 7 provides a kind of communicator, specifically can be a kind of sensor node, and mobile agent adopts above-mentioned mobile agent stroke planning method between said sensor node, to realize migration.Comprise: confirm unit 11, judging unit 12, the first migration units 13.

Wherein, confirm that unit 11 is used for if the accumulated value of information gain is not more than the information gain threshold value, confirm the position candidate of destination object in the next moment;

Judging unit 12 is used to judge that whether position and the distance between the said position candidate of host's sensor node at the current place of mobile agent be greater than first threshold;

First migration units 13 is used for not moving said mobile agent if said distance is not more than said first threshold; If said distance is greater than said first threshold, select target sensor node from neighbours' sensor node of host's sensor node at the current place of said mobile agent is moved to said objective sensor node with said mobile agent.

A kind of communicator that the embodiment of the invention provided; When if the position of host's sensor node at the current place of mobile agent and the distance of destination object between the position candidate in the next moment are not more than said first threshold; Do not move said mobile agent, thereby can reduce the number of times that mobile agent moves, especially; When the movement velocity of destination object is slow; Can overcome the problem that mobile agent frequently moves in the prior art, thereby reduce the energy consumption of WSN network, prolong the useful life of WSN network.

During practical application, said definite unit 11 specifically is used for confirming the position candidate of said destination object in the next moment according to the historical position of destination object and current location.

Further, when realizing obtaining the current location of said destination object, as shown in Figure 8, said communicator also comprises: receive and choose unit 14 and acquiring unit 15.

The beacon message of neighbours' sensor node that unit 14 is used to receive host's sensor node at the current place of said mobile agent is chosen in reception; According to the beacon message of neighbours' sensor node of the beacon message of said host's sensor node and said host's sensor node, choose first three maximum sensor node of measured value in all beacon messages;

Acquiring unit 15 be used for according to said three sensor nodes separately beacon message obtain the current location of said destination object.

At this moment, said first migration units 13 specifically is used for utilizing neighbours' sensor node position and dump energy select target sensor node from neighbours' sensor node of host's sensor node at the current place of said mobile agent of beacon message sensor node separately of host's sensor node at said position candidate, the current place of said mobile agent.

For example; Optional, a kind of mode of select target sensor node that realizes is: said first migration units specifically is used for according to

from neighbours' sensor node select target sensor node of host's sensor node at the current place of said mobile agent;

Wherein, j ^*Expression objective sensor node, and j ^*∈ N _k, 0≤a≤1, N _kRepresent the set of neighbours' sensor node of host's sensor node k at the current place of said mobile agent, e _j(t) dump energy of expression sensor node j, e _MaxThe initial energy value of expression sensor node, x ^Λ(t+1) the said destination object of expression is in the position candidate in the next moment, || x ^Λ(t+1)-x _j|| expression sensor node j is to the distance of said position candidate, ds _MaxThe maximum perceived distance of expression sensor node.

Further, the information gain of the maximum sensor node of measured value is used for being added to the accumulated value of said information gain in said three sensor nodes.

Further, cause the unbalanced problem of offered load for fear of single-sensor node short time internal consumption significant amount of energy, as shown in Figure 9, said communicator also comprises: statistic unit 16.

Statistic unit 16 is used to add up the number of times that said mobile agent does not move;

The number of times that said first migration units 13 also is used for not moving when said mobile agent is during greater than preset second threshold value; Select target sensor node from neighbours' sensor node of host's sensor node at the current place of said mobile agent is moved to said objective sensor node with said mobile agent.

Further, said mobile agent is moved to host's sensor node at the current place of said mobile agent by last sensor node, and said mobile agent is created in said last sensor node; In order to realize said mobile agent is moved to by last sensor node host's sensor node at the current place of said mobile agent; Shown in figure 10; This device also comprises: second migration units 17; Be used for according to the position of said destination object when said mobile agent is positioned at said last sensor node; From neighbours' sensor node of said last sensor node, select host's sensor node at said current place, said mobile agent is moved to host's sensor node at said current place.

For example; Optional, a kind ofly realize selecting the mode of host's sensor node at said current place to be: said second migration units 17 specifically is used for according to

selecting from neighbours' sensor node of said last sensor node host's sensor node at said current place;

Wherein, j ^*Host's sensor node of representing said current place, and j ^*∈ N _k, 0≤a≤1, N _kRepresent the set of neighbours' sensor node of said last host's sensor node k, e _j(0) dump energy of expression sensor node j, e _MaxThe initial energy value of expression sensor node, x ^Λ(0) position of the said destination object of expression when said mobile agent is positioned at said last sensor node, || x ^Λ(0)-x _j|| expression sensor node j is to the distance of the position of said destination object when said mobile agent is positioned at said last sensor node, ds _MaxThe maximum perceived distance of expression sensor node.

The embodiment of the invention is mainly used in the processing of moving agency's journey planning under the target tracking scene, can reduce the energy consumption of WSN network, prolongs the useful life of WSN network.

The above; Be merely embodiment of the present invention, but protection scope of the present invention is not limited thereto, any technical staff who is familiar with the present technique field is in the technical scope that the present invention discloses; Can expect easily changing or replacement, all should be encompassed within protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection range of said claim.

Claims (18)

1. a mobile agent stroke planning method is characterized in that, comprising:

If the accumulated value of information gain is not more than the information gain threshold value, confirm the position candidate of destination object in the next moment;

Whether position and the distance between the said position candidate of host's sensor node of judging the current place of mobile agent be greater than presetting first threshold;

If said distance is not more than said first threshold, do not move said mobile agent; If said distance is greater than said first threshold, select target sensor node from neighbours' sensor node of host's sensor node at the current place of said mobile agent is moved to said objective sensor node with said mobile agent.

2. mobile agent stroke planning method according to claim 1; It is characterized in that the position candidate of said definite destination object in the next moment comprises: historical position and current location according to destination object are confirmed the position candidate of said destination object in the next moment.

3. mobile agent stroke planning method according to claim 2 is characterized in that, also comprises:

Receive the beacon message of neighbours' sensor node of host's sensor node at the current place of said mobile agent; According to the beacon message of neighbours' sensor node of the beacon message of said host's sensor node and said host's sensor node, choose first three maximum sensor node of measured value in all beacon messages;

According to said three sensor nodes separately beacon message obtain the current location of said destination object.

4. mobile agent stroke planning method according to claim 3 is characterized in that, the information gain of the sensor node of measured value maximum is used for being added to the accumulated value of said information gain in said three sensor nodes.

5. mobile agent stroke planning method according to claim 3 is characterized in that, the select target sensor node comprises neighbours' sensor node of said host's sensor node from the current place of said mobile agent:

Utilize neighbours' sensor node position and dump energy select target sensor node from neighbours' sensor node of host's sensor node at the current place of said mobile agent of sensor node in the beacon message separately of host's sensor node at said position candidate, the current place of said mobile agent.

6. mobile agent stroke planning method according to claim 5; It is characterized in that, utilize said position candidate, the current place of said mobile agent host's sensor node neighbours' sensor node separately in the beacon message position and dump energy select target sensor node from neighbours' sensor node of host's sensor node at the current place of said mobile agent of sensor node comprise:

According to

from neighbours' sensor node of host's sensor node at the current place of said mobile agent the select target sensor node;

Wherein, j ^*Expression objective sensor node, and j ^*∈ N _k, 0≤a≤1, N _kRepresent the set of neighbours' sensor node of host's sensor node k at the current place of said mobile agent, e _j(t) dump energy of expression sensor node j, e _MaxThe initial energy value of expression sensor node, x ^Λ(t+1) the said destination object of expression is in the position candidate in the next moment, || x ^Λ(t+1)-x _j|| expression sensor node j is to the distance of said position candidate, ds _MaxThe maximum perceived distance of expression sensor node.

7. according to each described mobile agent stroke planning method of claim 1-6, it is characterized in that, also comprise:

Add up the number of times that said mobile agent does not move;

The number of times that does not move when said mobile agent is during greater than preset second threshold value; Select target sensor node from neighbours' sensor node of host's sensor node at the current place of said mobile agent is moved to said objective sensor node with said mobile agent.

8. according to each described mobile agent stroke planning method of claim 1-6; It is characterized in that; Said mobile agent is moved to host's sensor node at the current place of said mobile agent by last sensor node, and said mobile agent is created in said last sensor node; Host's sensor node that said mobile agent is moved to said current place by last sensor node comprises:

According to the position of said destination object when said mobile agent is positioned at said last sensor node; From neighbours' sensor node of said last sensor node, select host's sensor node at said current place, said mobile agent is moved to host's sensor node at said current place.

9. mobile agent stroke planning method according to claim 8; It is characterized in that; Said according to the position of said destination object when said mobile agent is positioned at said last sensor node, from neighbours' sensor node of said last sensor node, select host's sensor node at said current place to comprise:

From neighbours' sensor node of said last sensor node, select host's sensor node at said current place according to ;

Wherein, j ^*Host's sensor node of representing said current place, and j ^*∈ N _k, 0≤a≤1, N _kRepresent the set of neighbours' sensor node of said last host's sensor node k, e _j(0) dump energy of expression sensor node j, e _MaxThe initial energy value of expression sensor node, x ^Λ(0) position of the said destination object of expression when said mobile agent is positioned at said last sensor node, || x ^Λ(0)-x _j|| expression sensor node j is to the distance of the position of said destination object when said mobile agent is positioned at said last sensor node, ds _MaxThe maximum perceived distance of expression sensor node.

10. a communicator is characterized in that, comprising:

Confirm the unit, be used for confirming the position candidate of destination object in the next moment if the accumulated value of information gain is not more than the information gain threshold value;

Judging unit, whether position and the distance between the said position candidate of host's sensor node that is used to judge the current place of mobile agent be greater than first threshold;

First migration units is used for not moving said mobile agent if said distance is not more than said first threshold; If said distance is greater than said first threshold, select target sensor node from neighbours' sensor node of host's sensor node at the current place of said mobile agent is moved to said objective sensor node with said mobile agent.

11. communicator according to claim 10 is characterized in that, said definite unit specifically is used for confirming the position candidate of said destination object in the next moment according to the historical position of destination object and current location.

12. communicator according to claim 11 is characterized in that, also comprises:

The unit is chosen in reception; Be used to receive the beacon message of neighbours' sensor node of host's sensor node at the current place of said mobile agent; According to the beacon message of neighbours' sensor node of the beacon message of said host's sensor node and said host's sensor node, choose first three maximum sensor node of measured value in all beacon messages;

Acquiring unit, be used for according to said three sensor nodes separately beacon message obtain the current location of said destination object.

13. communicator according to claim 12 is characterized in that, the information gain of the sensor node of measured value maximum is used for being added to the accumulated value of said information gain in said three sensor nodes.

14. communicator according to claim 12; It is characterized in that said first migration units specifically is used for utilizing neighbours' sensor node position and dump energy select target sensor node from neighbours' sensor node of host's sensor node at the current place of said mobile agent of beacon message sensor node separately of host's sensor node at said position candidate, the current place of said mobile agent.

15. communicator according to claim 14; It is characterized in that said first migration units specifically is used for according to

from neighbours' sensor node select target sensor node of host's sensor node at the current place of said mobile agent;

Wherein, j ^*Expression objective sensor node, and j ^*∈ N _k, 0≤a≤1, N _kRepresent the set of neighbours' sensor node of host's sensor node k at the current place of said mobile agent, e _j(t) dump energy of expression sensor node j, e _MaxThe initial energy value of expression sensor node, x ^Λ(t+1) the said destination object of expression is in the position candidate in the next moment, || x ^Λ(t+1)-x _j|| expression sensor node j is to the distance of said position candidate, ds _MaxThe maximum perceived distance of expression sensor node.

16. according to each described communicator of claim 10-15, it is characterized in that, also comprise:

Statistic unit is used to add up the number of times that said mobile agent does not move;

The number of times that said first migration units also is used for not moving when said mobile agent is during greater than preset second threshold value; Select target sensor node from neighbours' sensor node of host's sensor node at the current place of said mobile agent is moved to said objective sensor node with said mobile agent.

17. according to each described communicator of claim 10-15; It is characterized in that; Said mobile agent is moved to host's sensor node at the current place of said mobile agent by last sensor node, and said mobile agent is created in said last sensor node; This device also comprises: second migration units; Be used for according to the position of said destination object when said mobile agent is positioned at said last sensor node; From neighbours' sensor node of said last sensor node, select host's sensor node at said current place, said mobile agent is moved to host's sensor node at said current place.

18. communicator according to claim 17; It is characterized in that said second migration units specifically is used for basis

is selected said current place from neighbours' sensor node of said last sensor node host's sensor node;

Wherein, j ^*Host's sensor node of representing said current place, and j ^*∈ N _k, 0≤a≤1, N _kRepresent the set of neighbours' sensor node of said last host's sensor node k, e _j(0) dump energy of expression sensor node j, e _MaxThe initial energy value of expression sensor node, x ^Λ(0) position of the said destination object of expression when said mobile agent is positioned at said last sensor node, || x ^Λ(0)-x _j|| expression sensor node j is to the distance of the position of said destination object when said mobile agent is positioned at said last sensor node, ds _MaxThe maximum perceived distance of expression sensor node.

Images