CN103607749A - A direction perception guided data collection method in an opportunity mobile sensor network - Google Patents

Abstract

The invention discloses a direction perception guided data collection method in an opportunity mobile sensor network. Any two mobile sensors which are s1 and s2 are representatively represented by i and j. Direction included angles of the two mobile sensors are respectively ai and aj. The direction perception guided data collection method comprises the following steps: (1), if i and j directly forward messages to an Sink node in a communication radius scope of a Sink node, and then clean clear a self message buffer memory in order to store new messages in a communication radius scope of the Sink node, data forwarding does not occur between the i and the j; (2), if the i and the j give priority to forwarding the data to the sensors which are in favor of approaching the Sink node outside the communication radius scope of the Sink node; (3) the data finally is forwarded to a backbone network by the Sink node to complete data collection. The direction perception guided data collection method in the opportunity mobile sensor network of the invention can substantially reduce message redundancy. The algorithm is simple and practical. The sensors are low in energy consumption. The network usefulness and the data collection success rate can be improved and a life cycle of the opportunity mobile sensor network can be prolonged.

Description

The method of data capture of directional perception guiding in a kind of chance mobile sensor network

Technical field

The present invention relates to mobile network's technical field, relate in particular to the method for data capture of directional perception guiding in a kind of chance mobile sensor network.

Background technology

Mobility aware system application is more and more extensive, as monitor ZebraNet and the TurtleNet of wild animal, in handheld device, embed sensing module and collect the city perception (urbansensing) of urban environment information, and sensor node is arranged on to the Cartel etc. that collects urban traffic conditions on vehicle.In these application, transducer is sparse deployment often, and the limited transducer of communication distance moves with object and changes, and is difficult to form the wireless network of a full-mesh, can only form locally connected, the wireless network of isolation and topological dynamic change mutually.The communication opportunity that Internet Addiction node motion is brought is realized the forwarding of data.Chance mobile sensor network adopts the pattern forwarding messages of " store-carry-forward ", be that node is after receiving message, storing message while there is no suitable forward node, while running into sink node or suitable forward node in moving process, just forward, realize in this way the data collection function of network.

There are at present several approximate technical schemes, a kind of Flooding mechanism that is called, be used for collecting whale sensor network data, transducer is embedded in it whale, by the data-message of generation being copied to the whale node meeting to each, in the time of near swimming across the sink node being deployed on jellyfish, upload the data to sink node.This mechanism is actually infection forwarding mechanism, if the buffer memory of sensor node is enough large, the data transmission success of this mechanism is just high, but network overhead is very large.Another is called SCAR(sensor context-aware routing) opportunistic data collection mechanism, for not being communicated with mobile sensor network, the transmission probability of each node association is not based on the aforesaid node situation of meeting, but defines based on node contextual information (comprising node neighbours rate of change, energy etc.).This mechanism estimates that the calculating of transmission probability is very complicated, is not most suitable on the sensor node of resource anxiety.The third is called the adaptive Data Collection mechanism of ADG (Adaptive Data Gathering), for the information gathering application with different transmission quality demands, associated one of each node continues " forwarding probability " parameter changing, " important factor " parameter of dynamically adjusting of each message relating, determine the number of copy times of message in network being aided with other parameter adaptives, make Data Collection mechanism can meet the requirement of data transmission performance, there is again little network overhead.Also have a kind of scheme, proposed a routing mechanism based on Virtual Space, adopt the transmission mode of " store-carry-forward " to realize Data Collection.Each sensor node is according to being mapped to a coordinate points in higher dimensional space with the expectation transmission delay of a plurality of sink nodes, and transmission of messages is corresponding to move to the process of space initial point from source node.

Chance mobile sensor network: transducer is sparse deployment often, the limited transducer of communication distance moves with object and changes, be difficult to form the wireless network of a full-mesh, can only form locally connected, isolation and the wireless network of topological dynamic change mutually, the communication opportunity that Internet Addiction node motion is brought is realized the forwarding of data.Perceived direction: mobile node is with respect to the instantaneous mobile trend of Sink node: convergence or away from Sink node, is called the perceived direction of mobile node.When two nodes meet, can calculate their perception to direction.Data retransmission: in Sensor Network, between the mobile node meeting, between mobile node and Sink node, Sink node and backbone network be shown in the transfer of data of carrying out.Data Collection: in sensing network, the data centralization that each transducer is detected is carried out Storage and Processing to data center.Forward redundancy: the number of times that same message is forwarded in Sensor Network or simultaneous copy number.Energy residue threshold value a: transducer maintains the needed minimum energy value of normal operation, lower than this value, transducer may can quit work at any time maybe can not guarantee normal operation.

In chance mobile sensor network, in existing method of data capture, ubiquitous shortcoming has: in (1) network, message redundancy is high; (2) data collection algorithm is complicated, and this is because the too much cause of constrained parameters; (3) network efficiency is poor, and data collection efficiency is lower; (4) sensor energy consumption is large, and life cycle is short.

For example: the first scheme Flooding mechanism, be actually infection forwarding mechanism, need sensor node to have enough large buffer memory guarantee data transmission success, message redundancy is very high, network overhead is very large, and data collection efficiency and transducer are all lower life cycle;

First scheme SCAR mechanism, estimates that the calculating of transmission probability is very complicated, and sensor energy consumption is large, is not most suitable on the sensor node of resource anxiety, and network efficiency and life cycle are short; The third option A DG (Adaptive Data Gathering) mechanism, associated one of each node continues " forwarding probability " parameter changing, " important factor " parameter of dynamically adjusting of each message relating, also have other parameters, data collection algorithm is too complicated, affects network efficiency and life cycle; The 4th kind of scheme and the third scheme are similar, face the challenge in actual applications.

Summary of the invention

The technical issues that need to address of the present invention are how to reduce message redundancy, reduce algorithm complex, improve Data Collection success rate and the life cycle of Sensor Network.

In order to solve above technical problem, the invention discloses the method for data capture of directional perception guiding in a kind of chance mobile sensor network, with i, j represents respectively any two movable sensor s ₁, s ₂, their angular separation is respectively α _i, α _j, comprise the following steps:

(1) if i, j, within the scope of the communication radius of Sink node, is directly transmitted to Sink node message, then empties the message buffering of self to store new message,, between j, there is not data retransmission in i;

(2) if i, j, outside Sink node communication radius, is transmitted to high priority data the transducer that is more conducive to approach Sink node;

(3) data are finally transmitted to backbone network by Sink node, complete Data Collection.

The present invention utilizes directional perception guiding, only need a small amount of restriction on the parameters can complete data retransmission, can significantly reduce that message redundancy, algorithm are simple and practical, sensor energy consumes littlely, can improve network efficiency and Data Collection success rate, extends the life cycle of chance mobile sensor network.

Accompanying drawing explanation

When considered in conjunction with the accompanying drawings, by the detailed description with reference to below, can more completely understand better the present invention and easily learn wherein many advantages of following, but accompanying drawing described herein is used to provide a further understanding of the present invention, form a part of the present invention, schematic description and description of the present invention is used for explaining the present invention, does not form inappropriate limitation of the present invention, wherein:

Fig. 1 is s in embodiment of the present invention chance mobile sensor network ₁and s ₂schematic diagram meets.

Fig. 2 is the embodiment of the present invention T random site distribution map of s1 constantly.

Fig. 3 is the location map after the embodiment of the present invention T+ τ instantaneous movement of s1 constantly.

Fig. 4 is that the embodiment of the present invention is with the Data Collection flow process figure of directional perception guiding.

Embodiment

With reference to Fig. 1-4 pair embodiments of the invention, describe.

For above-mentioned purpose, feature and advantage can be become apparent more, below in conjunction with the drawings and specific embodiments, the present invention is further detailed explanation.

In chance mobile sensor network, for two movable sensor i that meet, j, carries out data retransmission with technical scheme below, thereby realizes the Data Collection with perceived direction guiding.Method of data capture has only been used three constrained parameters: movable sensor is with respect to communication angle β, perceived direction α and their the energy residue E of Sink node, and data collection algorithm is simple and practical.That concrete technical scheme is described below:

(1) movable sensor i, when j meets, calculates at a distance of nearest Sink node

Movable sensor i, j uses respectively s ₁and s ₂represent, as shown in Figure 1, work as s ₁and s ₂while meeting, can be by s in data fields ₁, s ₂be considered as a point, the distance of this point and Sink1, Sink2 and Sink3 is respectively d ₁, d ₂and d ₃.The positive radius of communication of each Sink node is r, form take node as the center of circle, the r communication circle that is radius.

Generally, think that the spacing between Sink node is far longer than its positive radius of communication r.As two transducer s ₁, s ₂while meeting, the position of supposing them is (x ₀, y ₀), the position of Sink node is (x _k, y _k), k=1,2,3, while meeting and the distance of each Sink node

as seen from Figure 1, d ₁≤ d ₂≤ d ₃.Now, s ₁, s ₂when carrying out perceived direction calculating, by their nearest Sink1 nodes of chosen distance, be basic point.

(2) movable sensor i, when j meets, calculates communication angle β separately

Movable sensor i, j uses respectively s ₁and s ₂represent, as shown in Figure 2, at T constantly, set up and take the X-Y rectangular coordinate system that Sink node is initial point, the position of establishing Sink node is (0,0), certain movable sensor s ₁position be (x ₁, y ₁).Γ ₁for s ₁with respect to the normal equation of Sink node, Ψ ₁for passing through s ₁and and Γ ₁vertical straight line, can construct T constantly with s ₁Γ for initial point ₁-Ψ ₁coordinate system.In addition, v ₁representative is at T moment s ₁instantaneous rate travel and direction, v ₁with Γ ₁angle be α, claim that α is T s constantly ₁angular separation with respect to Sink node.F ₁to pass through s ₁sink communication circle tangent line, F ₁with Γ ₁angle be β, this angle is called s ₁communication angle, obviously

wherein

in like manner can calculate s ₂communication angle.

(3) movable sensor i, when j meets, calculates T moment perceived direction α separately

Movable sensor i, j uses respectively s ₁and s ₂represent s ₁in T position constantly as shown in Figure 3, the moment after meeting, supposed to pass through the movement of a utmost point short time τ (τ → 0), now T+ τ s constantly ₁moved to s' ₁position, angular separation is α '.After movement, Γ ₁-Ψ ₁having there is minor variations in coordinate system, has become T+ τ Γ ' constantly ₁-Ψ ' ₁coordinate system, as shown in Figure 3.Γ ' ₁, Γ ₁and limit (s ' ₁, s ₁) form a triangle, Γ ' ₁with Γ ₁angle be δ, limit (s' ₁, s ₁) and Γ ₁angle be γ, s' ₁position coordinates be (x' ₁, _y' ₁).So, can make following calculating:

$\left\{\begin{array}{c}a=|({\mathrm{<figure-callout\; id="1"\; label="s"\; filenames="HDA0000415537480000012.png"\; state="\{\{state\}\}">s</figure-callout>}}_1^{\&prime;},\mathrm{Sink})=\sqrt{x_1^{\&prime;2}+{\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="HDA0000415537480000012.png"\; state="\{\{state\}\}">y</figure-callout>}}_1^{\&prime;2}}\\ b=\left|({\mathrm{<figure-callout\; id="1"\; label="s"\; filenames="HDA0000415537480000012.png"\; state="\{\{state\}\}">s</figure-callout>}}_1,\mathrm{Sink})\right|=\sqrt{{x_1}^2+{y_1}^2}\\ c=\left|({\mathrm{<figure-callout\; id="1"\; label="s"\; filenames="HDA0000415537480000012.png"\; state="\{\{state\}\}">s</figure-callout>}}_1^{\&prime;},s_1)\right|=\sqrt{{(x_1^{\&prime;}-x_1)}^2+{(y_1^{\&prime;}-y_1)}^2}\end{array}\right.---\left(1\right)$

$\left\{\begin{array}{c}\cos \mathrm{\&gamma;}=\frac{{\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA0000415537480000012.png"\; state="\{\{state\}\}">b</figure-callout>}}^2+c^2-{\mathrm{<figure-callout\; id="2"\; label="a"\; filenames="HDA0000415537480000012.png"\; state="\{\{state\}\}">a</figure-callout>}}^2}{2\mathrm{bc}}\\ \mathrm{\&gamma;}=\arccos \left(\frac{{\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HDA0000415537480000012.png"\; state="\{\{state\}\}">b</figure-callout>}}^2+c^2-{\mathrm{<figure-callout\; id="2"\; label="a"\; filenames="HDA0000415537480000012.png"\; state="\{\{state\}\}">a</figure-callout>}}^2}{2\mathrm{bc}}\right)\end{array}\right.---\left(2\right)$

By upper two formulas, can obtain γ.Due to τ → 0, s ₁movement very little, therefore can be similar to and think and use now s by α=γ ₁angular separation α s while representing that T constantly ₁perceived direction.In like manner also can calculate s ₂in T perceived direction constantly.

As shown in Figure 4, with i, j represents respectively above-mentioned any two movable sensor s ₁, s ₂, their angular separation (being also perceived direction) is respectively α _i, α _j, as shown in Figure 4, with the method for data capture of perceived direction guiding, concrete grammar is as follows for the Data Collection flow process guiding with directional perception:

S1, i, two movable sensors of j meet;

S2, judge whether in Sink node communication radius?

S3, i, j, within the scope of the communication radius of Sink node, is directly transmitted to Sink node message, then empties the message buffering of self to store new message, and, there is not data retransmission in i, finishes (S14) between j;

If S4 is outside Sink node communication radius, first inquire about i, the energy residue E situation of j, the principle of data retransmission is: not data retransmission to E value the transducer lower than its threshold value because E value is too low, transducer may quit work at any time, if two transducer E values, all lower than its threshold value, do not forward, mutually to save energy, guarantee Data Collection reliability, finish (S14);

If S7 is i, the E value of j is not all lower than its threshold value, calculates the Sink node that they meet nearest; S8, then calculate communication angle β separately; S5, calculating perceived direction α separately _iand α _j;

S9, judgement i, whether j perceived direction is all less than communication angle separately; If S10 is α _i, α _jall be less than communication angle β separately, i, there is not data retransmission in j, finishes (S14) yet; S11, judgement α _i< α _jset up? if S12 is α _i< α _j, j gives i data retransmission, finishes (S14); If S13 is α _i> α _j, i gives j data retransmission, finishes (S14).In a word, the message of the perceived direction of take guiding forward route as: high priority data is transmitted to the transducer that is more conducive to approach Sink node, to improve data retransmission to the probability of Sink node;

Data are finally transmitted to backbone network by Sink node, complete Data Collection.

Although more than described the specific embodiment of the present invention, but those skilled in the art is to be understood that, these embodiments only illustrate, those skilled in the art, in the situation that not departing from principle of the present invention and essence, can carry out various omissions, replacement and change to the details of said method and system.For example, merge said method step, thereby carry out the identical function of essence according to the identical method of essence, to realize the result that essence is identical, belong to scope of the present invention.Therefore, scope of the present invention is only limited by appended claims.

Claims (3)

1. a method of data capture for directional perception guiding in chance mobile sensor network, uses i, and j represents respectively any two movable sensor s ₁, s ₂, their angular separation is respectively α _i, α _j, it is characterized in that, comprise the following steps:

(1) if i, j, within the scope of the communication radius of Sink node, is directly transmitted to Sink node message, then empties the message buffering of self to store new message,, between j, there is not data retransmission in i;

(2) if i, j, outside Sink node communication radius, is transmitted to high priority data the transducer that is more conducive to approach Sink node;

(3) data are finally transmitted to backbone network by Sink node, complete Data Collection.

2. the method for data capture of directional perception guiding in chance mobile sensor network according to claim 1, is characterized in that, in described step (2), first inquire about i, the energy residue E situation of j, if two transducer E values are all lower than its threshold value, does not forward mutually.

3. the method for data capture of directional perception guiding in chance mobile sensor network according to claim 1, it is characterized in that, describedly high priority data is transmitted to the transducer that is more conducive to approach Sink node specifically comprises: calculate the Sink node that they meet nearest, then calculate communication angle β separately, calculate perceived direction α separately _iand α _j; If α _i, α _jall be less than communication angle β separately, i, there is not data retransmission in j yet; Otherwise: if α _i< α _j, j gives i data retransmission; If α _i> α _j, i gives j data retransmission.

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