CN103442336A - Data distribution method based on link relevance in wireless sensor network - Google Patents

Abstract

The invention discloses a data distribution method based on link relevance in a wireless sensor network. The method comprises the following steps that in an initialization phase, each node obtains hop counts from the node to a root node by receiving and broadcasting HOP information, then, HELLO information is broadcast, and each node records the receiving state of the heard HELLO information; in a relevance tree construction phase, the nodes send and receive CLAIM information, the link quality and the link relevance are calculated, father nodes are selected, and a relevance tree is established according to the set membership between the nodes; in an encoding decision phase, the nodes establish a decision model with encoding and a decision model without encoding, transmission delay in the two decision models is calculated, and the decision model with the smaller transmission delay is selected to be used as the final encoding strategy; in a data distribution phase, the nodes distribute data according to the established relevance tree and the selected encoding strategy in the previous steps, and a preferential request mechanism is used for ensuring reliability and efficiency in the data distribution process.

Description

Data distributing method based on the link correlation in a kind of radio sensing network

Technical field

The invention belongs to wireless self-organization network and sensor network field, relate to a kind of implementation method of Data dissemination agreement of link correlation, upgrade for the speed code that realizes the radio sensing network node.

Background technology

Along with embedded, the transducer manufacture, the development of wireless communication technology, the massive wireless sensor technology develops and is widely applied to the numerous areas such as military surveillance, public safety, intelligent transportation, environment measuring, medical monitoring rapidly.Typical wireless sensor network is comprised of a large amount of microsensor nodes, they are deployed in the adverse circumstances of unmanned monitoring, and control with procotol and automatically form the multihop network system by topology from forming net by wireless, be not subject to the restriction of existing cable network infrastructure.Perception data is pooled to data processing centre by radio communication in the multi-hop relay mode.Wireless sensor network make people at any time and place with environmental condition under a large amount of accurate and reliable information of Real-time Obtaining, the mankind have been stretched to long-range nerve endings all things on earth in the external world seemingly.Just because of the large coverage of sensor network scale is wide, make the code update of institute's length of run order on sensor node run into a lot of challenges.Existing Data dissemination agreement can completion code renewal, but ignored the objective fact that the link correlation exists, make the efficiency of Data dissemination not high, can not effectively reduce deadline and data transfer overhead.

Summary of the invention

The purpose of this invention is to provide in a kind of radio sensing network the data distributing method relevant based on link, upgrade for the speed code that realizes the radio sensing network node.

For achieving the above object, the technical solution used in the present invention is as follows:

Data distributing method based on the link correlation in radio sensing network of the present invention comprises the steps:

Step 1: by a HOP message of root node broadcast, described HOP message only has a field jumping figure, and described field jumping figure is the jumping figure of non-root node to root node, and the initial value of described field jumping figure is 0; After non-root node is received described HOP message for the first time, the value of field jumping figure is added to 1 and write down the jumping figure as this non-root node to root node, then non-root node is gone out amended HOP information broadcast again;

Each node is broadcasted mutually HELLO message, and the ID that described HELLO message comprises sending node, sending node are to the jumping figure of root node and increase progressively sequence number; Node receives only the HELLO message of downstream node, and the jumping figure that described downstream node refers to root node adds 1 node for this node to the jumping figure of root node; The downstream node of hearing is designated as to the child node of this node; and use bit vector to record the accepting state of up-to-date 10 HELLO message of each child node; wherein; it in described bit vector, has been HELLO information drop-out that 1 bit representation is corresponding; be that 0 HELLO message corresponding to bit representation successfully receives, each child node takies a bit vector;

Step 2: CLAIM message of each node broadcasts; the ID that described CLAIM message comprises sending node and a key-value pair set, each key-value pair of described key-value pair set consists of the bit vector of the HELLO message of the ID of the child node of sending node, each corresponding child node of expression that sending node records;

Each node is according to received CLAIM message; link-quality according to formula (1) computing node to each sending node; link correlation according to the link between the child node of formula (2) computing node and each sending node; and then calculate the factor of influence of each sending node according to formula (3); select the sending node of value maximum of factor of influence as father node, and set up the correlation tree according to internodal set membership;

$q_{\mathrm{ik}}=1-\frac{{\mathrm{\Σ}}_{m=0}^{m=\left|B_{\mathrm{ik}}\right|}{B}_{\mathrm{ik}}\left(m\right)}{\left|B_{\mathrm{ik}}\right|}---\left(1\right)$

m _k(i)=αc _i(k,S)+(1-α)q _ik (3)

In formula (1), (2) and (3):

I means to send the node of CLAIM message,

K means to receive the node of CLAIM message,

B _ikthe bit vector of the HELLO message that the node k that the expression node i records sends,

| B _ik| mean the mould of bit vector,

Q _ikthe link-quality that means link i → k,

S means the set (s of the residue child node that does not comprise node k of node i ₁, s ₂... s _n),

B _iSthe new bit vector obtained after the bit vector AND operation bit-by-bit of the HELLO message that the residue child node that does not comprise node k that the expression node i records sends;

B _ik(m) mean B _ikthe value of m position;

B _iS(m) mean B _iSthe value of m position;

C _ilink i → k that (k, S) expression node k calculates is to the link correlation of link set i → S;

P _i(S|k) the conditional probability mathematical notation mode of representation formula (2);

α means the weighted average factor, and the interval of α is [0,1];

M _k(i) mean the factor of influence of the node i that node k calculates;

After the selected father node of each non-root node, broadcast a PSLT message informing neighbor node, the ID of the ID that described PSLT message comprises this non-root node and selected father node;

Step 3: set up suc as formula the decision model of the coding of the use shown in (4) and the decision model of not using coding shown in formula (5),

$t_{\mathrm{coding}}=\frac{N}{q_{\mathrm{iw}}}\mathrm{\τ}+\frac{1}{q_{\mathrm{iw}}}{t}_{\mathrm{REQ}}+D---\left(4\right)$

$t_{\mathrm{native}}={\mathrm{NE}}_{\mathrm{pkt}}\mathrm{\τ}+\frac{1}{q_{\mathrm{iw}}}{t}_{\mathrm{REQ}}---\left(5\right)$

Wherein, $E_{\mathrm{pkt}}={\mathrm{\Σ}}_{k=1}^{+\∞}k{P}_n^i\{X=r\}---\left(6\right)$

In formula (6)

by formula (7) and stepping type (8), calculated:

$P_n^i\{X=r\}=P_n^i\{X>r-1\}-P_n^i\{X>r\}---\left(7\right)$

$P_n^i\{X>r\}={(1-q_{\mathrm{in}})}^r+P_{n-1}^i\{X>r\}-{((1-q_{\mathrm{in}})\×P_{(n-1)/n}^i)}^r$

$={\mathrm{\Σ}}_{m=1}^n{(1-q_{\mathrm{im}})}^r-((1-q_{\mathrm{im}})\×P_{(m-1)/m}^i{)}^r)(P_{0/1}^1=0)---\left(8\right)$

Formula (4) arrives in formula (8),

N means the quantity of the packet that the individual data page comprises;

τ means the transmission time of individual data bag;

Decode time when D means to use network code;

N means the node number in the S set of child node of node i;

Q _ikthe link-quality that means link i → k;

W means the child node that the link-quality of node i is the poorest, q _iw=min _{k ∈ S}(q _ik);

T _rEQthe time that means the packet that request is lost;

E _pktmean that the individual data bag will cover n the expectation transmission value that child node is required;

T _codingmean the transmission delay of individual data page when using coding;

T _nativemean the transmission delay of individual data page when not using coding;

R means the number of transmissions of individual data bag;

the individual data bag that means node i sends the probability that can cover n child node for r time;

the individual data bag that means node i sends the probability that can not cover n child node for r time;

(1-q _in) ^rthe individual data bag that means node i sends the probability that can not cover child node n for r time;

the individual data bag that means node i sends the probability that can not cover n-1 child node except child node n for r time;

be illustrated in the probability in the packet set that packet that node n loses is comprised in a remaining n-1 node loss; According to formula (2), calculate $P_{(n-1)/n}^i=c_i(n,S_{n-1})=P_i\left(S_{n-1}\right|n),$ Wherein, S _n-1mean the set of n-1 remaining node;

the individual data bag that means node i sends r time, can not cover child node n, can not cover the probability of a remaining n-1 child node;

Calculate to use respectively the coding decision model of coding and do not use the transmission delay of the coding decision model of coding, therefrom select coding decision model that transmission delay value the is less final coding strategy as each node;

Step 4: correlation tree and selected final coding strategy that each node is set up according to above step are gone out Data dissemination, and whole distribution procedure is started by root node.

Further, the present invention in step 4, when child node often receive one take turns data after, if loss of data is arranged, just trigger a timer, sent the request of the data of retransmission of lost to father node by child node; The timing interval of described timer is suc as formula shown in (9):

Δt=Cn×q _ik+T _r (9)

In formula (9), Cn means to be greater than 100 integer, q _ikmean the link-quality of father node i to child node k, T _rmean the random number in 0 to 8 scope; Child node is poorer to the link-quality of father node, and the timing interval of delta t is shorter.

Compared with prior art, the invention has the beneficial effects as follows: the inventive method has been considered the impact of link correlation in the Data dissemination process, has reduced the deadline of the Data dissemination of transport overhead, the energy consumption of node, whole network.

The accompanying drawing explanation

Fig. 1 is the mechanical flow diagram of the inventive method.

Fig. 2 is a data distribution topological diagram, and in figure, node A and B send out 10 packets to node C, D and E; Wherein, grey rectangle means that corresponding packet successfully receives, and white rectangle has meaned corresponding data-bag lost, needs next round to retransmit; R is root node.

Fig. 3 is the correlation tree that utilizes the inventive method to set up.

Embodiment

Can realize the data distributing method based on the link correlation in radio sensing network of the present invention in Embedded Network Operating System TinyOS2.1.1.As shown in Figure 1, Fig. 2 is the Data dissemination topological diagram of one embodiment of the present of invention to workflow of the present invention, and the father node of node A and B is all root node R.Below in conjunction with Fig. 2, the invention will be further described.

(1) initial phase.

At first by the R HOP message of going on the air, described HOP message only has a field jumping figure h _r=0.After A, B hear this HOP message for the first time, obtain the value of the field jumping figure in HOP message, carry out and calculate h _a=h _r+ 1=1, the jumping figure as A to R, in like manner B is to the jumping figure h of R _b=1.A, B encapsulate the value of amended field jumping figure respectively in HOP message and broadcast away, hear afterwards all no longer processing of any HOP message.C, D have heard the message of the HOP of A, calculate the jumping figure h that arrives separately R _c(h _d)=h _a+ 1=2, E has heard the HOP message of B, calculates oneself jumping figure h to R _e=h _b+ 1=2, the effect of HOP message is to prevent from loop occurring at correlation tree construction phase.

Each node is broadcasted mutually HELLO message, and the ID that described HELLO message comprises sending node, sending node are to the jumping figure of root node and increase progressively sequence number; ID, the C that the HELLO message of C comprises C is to the jumping figure h of R _cwith increase progressively sequence number; Increasing progressively sequence number is for identifying the uniqueness of HELLO message, and such as the sequence number that increases progressively of current HELLO message is 1, the sequence number that increases progressively of so next HELLO message is just 2; A, B receive only the HELLO message of downstream node C, D, E; The child node of A using the downstream node C, the D that hear as A, the child node of B using the downstream node D, the E that hear as B; Four large rectangles in Fig. 2 mean respectively the bit vector B of the HELLO message of C, D that A records _aCand B _aD, the bit vector B of the HELLO message of the D that B records, E _bDand B _bE.Each large rectangle comprises 10 little rectangles, means up-to-date 10 HELLO message of each child node, and the little rectangle of white has meaned corresponding HELLO information drop-out, and the place value of the corresponding position of its bit vector is 1, for example bit vector B _aC={ 0,0,0,0,0,1,1,0,1,1}, its place value B of the 9th _aC(9)=1, meaned the 9th HELLO information drop-out.

(2) correlation tree construction phase

CLAIM message of each node broadcasts; the ID that described CLAIM message comprises sending node and a key-value pair set, the bit vector of the corresponding HELLO message that each key-value pair of described key-value pair set is recorded by ID, the sending node of the child node of sending node forms; Be shown<the A of CLAIM message table of A in Fig. 2 for example, { [C, B _aC], [D, B _aD].

Node D has heard the CLAIM message of Node B, calculates the link-quality of B → D according to formula (1):

$q_{\mathrm{BD}}=1-\frac{{\mathrm{\&Sigma;}}_{m=0}^{m=\left|B_{\mathrm{BD}}\right|}{B}_{\mathrm{BD}}\left(m\right)}{\left|B_{\mathrm{BD}}\right|}=1-\frac{4}{10}=60\%$

The link-quality that in like manner can obtain other 3 links is respectively 60%, 70%, 50%, as shown in Figure 2.

Calculate the correlation c of link B → D to link B → S according to formula (2) again _b(D, S), S is the residue child node set of the Node B except child node D, only has node E in accompanying drawing 2 in S.

In like manner can obtain c _a(D, S)=0, and then calculated respectively the factor of influence of sending node A, B by formula (3), get α=0.5, selects the sending node of value maximum of factor of influence as father node, according to internodal set membership, sets up the correlation tree.

m _D(A)=αc _A(D,S)+(1-α)q _AD=0.5×0+0.5×0.7=0.35

m _D(B)=αc _B(D，S)+(1-α)q _BD=0.5×1+0.5×0.6=0.8

So D selects B as its father node, the correlation tree of finally setting up as shown in Figure 3.

(3) the codes selection stage.

After correlation tree construction complete, node is set up the decision model of using coding and sets up the Policy model that does not use coding according to formula (5) according to formula (4), calculate respectively two kinds of transmission delays under strategy, select the less the most final coding strategy of strategy of transmission delay.

Take in Fig. 2 B and child node D, E is example, supposes N=20, τ=1ms, D=570ms, t _rEQ=20ms, B is poor to the link-quality of E, so q _iw=q _bE=0.5.

When final coding strategy is encoded for using, the transmission delay of individual data page is calculated as follows:

$t_{\mathrm{coding}}=\frac{N}{q_{\mathrm{iw}}}\mathrm{\&tau;}+\frac{1}{q_{\mathrm{iw}}}{t}_{\mathrm{REQ}}+D=\frac{20}{0.5}+\frac{1}{0.5}\&times;20+570=650\left(\mathrm{ms}\right)$

When final coding strategy is encoded for not using, at first calculate the expectation transmission value of B

$E_{\mathrm{pkt}}=\frac{1}{q_{\mathrm{BD}}}+\frac{1}{q_{\mathrm{BE}}}-\frac{1}{1-(1-q_{\mathrm{BD}})\&times;P_{E/D}^B}$

mean that data that E loses can comprise the probability of the packet that D loses, mean that D and E lose the probability of same packet,

mean that D and E have at least a node to receive the probability of packet.

In Fig. 2,

mean that the packet that D loses is comprised in the packet of E loss, the link-quality of link B → E is poor, and the expectation transmission value of B is that the child node the poorest by link-quality determines, so

and then the transmission delay of individual data page is

$t_{\mathrm{native}}={\mathrm{NE}}_{\mathrm{pkt}}+\frac{1}{q_{\mathrm{iw}}}{t}_{\mathrm{REQ}}=20\&times;2+\frac{1}{0.5}\&times;20=80\left(\mathrm{ms}\right)$

Because t _native<t _codingso Node B is selected not use the strategy of coding as its final coding strategy.

(4) the Data dissemination stage.

The inventive method is carried out the distribution of data according to the correlation tree (as shown in Figure 3) of having set up and final coding strategy.

Start distributing data by root node, in the Data dissemination process, by following mechanism, dissolve possible conflict.The first, when node A will send data page n, if listen to nodes B, sending data page n-1, it delays the transmission of data page n.The second, sending data page n if node A listens to nodes B, and the ID of Node B is less, node A just delays the transmission of data page n.

The inventive method reduces the transmission of request message and packet by a kind of override requests mechanism.When child node D, E often receive one take turns data after, if loss of data is arranged, just trigger a timer, send the request of the data of retransmission of lost to father node, the timing interval through type (9) of described timer calculates: suppose Cn=128, the timing interval of D, E is respectively calculated as follows

Δt(D)=Cn×q _BD+T _r=128×0.6+5=81(ms)

Δt(E)=Cn×q _BE+T _r=128×0.5+6=70(ms)

So the timer of E first triggers than D, (sequence number is 0 to the packet of first losing to father node B request, 2,3,5,7),, when the timer of D triggers, B may transmit Sequence Number as (0,2,3,5,7) packet, then four packets are also just in time that D loses, so D now just can directly receive packet, and no longer need to send request.

Claims (2)

1. the data distributing method based on the link correlation in a radio sensing network, is characterized in that, comprises the steps:

Step 1: by a HOP message of root node broadcast, described HOP message only has a field jumping figure, and described field jumping figure is the jumping figure of non-root node to root node, and the initial value of described field jumping figure is 0; After non-root node is received described HOP message for the first time, the value of field jumping figure is added to 1 and write down the jumping figure as this non-root node to root node, then non-root node is gone out amended HOP information broadcast again;

Each node is broadcasted mutually HELLO message, and the ID that described HELLO message comprises sending node, sending node are to the jumping figure of root node and increase progressively sequence number; Node receives only the HELLO message of downstream node, and the jumping figure that described downstream node refers to root node adds 1 node for this node to the jumping figure of root node; The downstream node of hearing is designated as to the child node of this node, and use bit vector to record the accepting state of up-to-date 10 HELLO message of each child node, wherein, it in described bit vector, has been HELLO information drop-out that 1 bit representation is corresponding, be that 0 HELLO message corresponding to bit representation successfully receives, each child node takies a bit vector;

Step 2: CLAIM message of each node broadcasts, the ID that described CLAIM message comprises sending node and a key-value pair set, each key-value pair of described key-value pair set consists of the bit vector of the HELLO message of the ID of the child node of sending node, each corresponding child node of expression that sending node records;

Each node is according to received CLAIM message, link-quality according to formula (1) computing node to each sending node, link correlation according to the link between the child node of formula (2) computing node and each sending node, and then calculate the factor of influence of each sending node according to formula (3), select the sending node of value maximum of factor of influence as father node, and set up the correlation tree according to internodal set membership;

$q_{\mathrm{ik}}=1-\frac{{\mathrm{\&Sigma;}}_{m=0}^{m=\left|B_{\mathrm{ik}}\right|}{B}_{\mathrm{ik}}\left(k\right)}{\left|B_{\mathrm{ik}}\right|}---\left(1\right)$

m _k(i)＝αc _i(k，S)+(1-α)q _ik (3)

In formula (1), (2) and (3):

I means to send the node of CLAIM message,

K means to receive the node of CLAIM message,

B _ikthe bit vector of the HELLO message that the node k that the expression node i records sends,

| B _ik| mean the mould of bit vector,

Q _ikthe link-quality that means link i → k,

S means the set (s of the residue child node that does not comprise node k of node i ₁, s ₂... s _n),

B _iSthe new bit vector obtained after the bit vector AND operation bit-by-bit of the HELLO message that the residue child node that does not comprise node k that the expression node i records sends;

B _ik(m) mean B _ikthe value of m position;

B _iS(m) mean B _iSthe value of m position;

C _ilink i → k that (k, S) expression node k calculates is to the link correlation of link set i → S;

P _i(S|k) the conditional probability mathematical notation mode of representation formula (2);

α means the weighted average factor, and the interval of α is [0,1];

M _k(i) mean the factor of influence of the node i that node k calculates;

After the selected father node of each non-root node, broadcast a PSLT message informing neighbor node, the ID of the ID that described PSLT message comprises this non-root node and selected father node;

Step 3: set up suc as formula the decision model of the coding of the use shown in (4) and the decision model of not using coding shown in formula (5),

$t_{\mathrm{coding}}=\frac{N}{q_{\mathrm{iw}}}\mathrm{\&tau;}+\frac{1}{q_{\mathrm{iw}}}{t}_{\mathrm{REQ}}+D---\left(4\right)$

$t_{\mathrm{native}}={\mathrm{NE}}_{\mathrm{pkt}}\mathrm{\&tau;}+\frac{1}{q_{\mathrm{iw}}}{t}_{\mathrm{REQ}}---\left(5\right)$

Wherein, $E_{\mathrm{pkt}}={\mathrm{\&Sigma;}}_{k=1}^{+\&infin;}k{P}_n^i\{X=r\}---\left(6\right)$

In formula (6)

by formula (7) and stepping type (8), calculated:

$p_n^i\{X=r\}=P_n^i\{X>r-1\}-P_n^i\{X>r\}---\left(7\right)$

$P_n^i\{X>r\}={(1-q_{\mathrm{in}})}^r+P_{n-1}^i\{X>r\}-{((1-q_{\mathrm{in}})\&times;P_{(n-1)/n}^i)}^r$ $={\mathrm{\&Sigma;}}_{m=1}^n{(1-q_{\mathrm{im}})}^r-{((1-q_{\mathrm{im}})\&times;P_{(m-1)/m}^i)}^r)(P_{0/1}^1=0)---\left(8\right)$

Formula (4) arrives in formula (8),

N means the quantity of the packet that the individual data page comprises;

τ means the transmission time of individual data bag;

Decode time when D means to use network code;

N means the node number in the S set of child node of node i;

Q _ikthe link-quality that means link i → k;

W means the child node that the link-quality of node i is the poorest, q _iw=min _{k ∈ S}(q _ik);

T _rEQthe time that means the packet that request is lost;

E _pktmean that the individual data bag will cover n the expectation transmission value that child node is required;

T _codingmean the transmission delay of individual data page when using coding;

T _nativemean the transmission delay of individual data page when not using coding;

R means the number of transmissions of individual data bag;

the individual data bag that means node i sends the probability that can cover n child node for r time;

the individual data bag that means node i sends the probability that can not cover n child node for r time;

(1-q _in) ^rthe individual data bag that means node i sends the probability that can not cover child node n for r time;

the individual data bag that means node i sends the probability that can not cover n-1 child node except child node n for r time;

be illustrated in the probability in the packet set that packet that node n loses is comprised in a remaining n-1 node loss; According to formula (2), calculate

$P_{(n-1)/n}^i=c_i(n,S_{n-1})=P_i\left(S_{n-1}\right|n),$ Wherein, S _n-1mean the set of n-1 remaining node;

the individual data bag that means node i sends r time, can not cover child node n, can not cover the probability of a remaining n-1 child node;

Calculate to use respectively the coding decision model of coding and do not use the transmission delay of the coding decision model of coding, therefrom select coding decision model that transmission delay value the is less final coding strategy as each node;

Step 4: correlation tree and selected final coding strategy that each node is set up according to above step are gone out Data dissemination, and whole distribution procedure is started by root node.

2. the data distributing method based on the link correlation in radio sensing network according to claim 1, it is characterized in that: in step 4, when child node often receive one take turns data after, if loss of data is arranged, just trigger a timer, sent the request of the data of retransmission of lost by child node to father node; The timing interval of described timer is suc as formula shown in (9):

Δt＝Cn×q _ik+T _r (9)

In formula (9), Cn means to be greater than 100 integer, q _ikmean the link-quality of father node i to child node k, T _rmean the random number in 0 to 8 scope; Child node is poorer to the link-quality of father node, and the timing interval of delta t is shorter.

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