CN102740394B - Center calculation wireless sensor network 2-node disjoint multipath routing algorithm - Google Patents

Abstract

The invention relates to a center calculation wireless sensor network 2-node disjoint multipath routing algorithm which adopts a central-dispatching type adaptive route maintenance mechanism to enhance the flexibility of the path maintenance. During the data routing, a data package only needs to carry a path bit sequence, and meanwhile, no control cost is required. According to the disjoint multipath routing algorithm, the hop count and the quality of the link are taken as metrics, the approximately optimal 2-node disjoint path from source node to the sink node is calculated by utilizing the whole network information, and then the micro-routing table containing main nodes, auxiliary nodes and the path bit sequence is generated and then transmitted to the nodes.

Description

The wireless sensor network 2-nonintersecting paths routing algorithm of center calculation

Technical field

The present invention relates to a kind of wireless sensor network 2-nonintersecting paths routing algorithm of center calculation.

Background technology

In wireless sensor network, than single path routing mechanism, multi-path routing mechanism has obvious advantage at aspects such as improving network reliability, equally loaded, fault-tolerant recovery.But, in multipath route, in the mulitpath from source node to destination node, may contain common node (link), the inefficacy of common node (link) can cause by the failure of its mulitpath.For fear of the appearance of common node (link), researcher has proposed disjoint multiple paths mechanism.

The people such as Preetha Thulasiraman have proposed the non-intersect routing algorithm of a kind of distributed 2-, first this algorithm builds mangrove and two color trees of greenery in network, and the mode increasing by path is in the mode of depth-first search, to set up two nonintersecting paths from each node to sink node from sink node.Algorithm can meet the non-intersect constraint of two paths, but the path that algorithm is set up is longer, and can not avoid the existence of ultra-long route, and in algorithm, the broadcast of control information can cause more energy consumption simultaneously.Similarly, also can first to the immediate neighbor of sink node, identify different colors, then by colour code, broadcast and find the node that colour code meets, thereby set up source node to the k-nonintersecting paths of sink node, the time complexity of algorithm is only O (L) (L is the limit number in network), but this algorithm still cannot be optimized effectively to path.In addition someone has proposed the nonintersecting paths routing algorithm based on geographical location information, these two kinds of algorithms are distributed algorithm equally, their weak point is that each node must know the geographical location information of self and its neighbor node, and cannot obtain equally source node to the optimum disjoint multiple paths of destination node.

At MPR(multipath routing, multipath route) in algorithm, DMPR (disjoint multipath routing, disjoint multiple paths route) algorithm has higher reliability and fault-tolerance.The main challenge that DMPR algorithm faces has 2 points: the one, nonintersecting paths select excellent problem, the 2nd, the transmission problem of packet on nonintersecting paths.

Summary of the invention

Object of the present invention is exactly for addressing the above problem, for example, for network topology in some commercial Application (mine environmental monitoring) more stable, the features such as the computing of sink node and storage capacity are stronger, a kind of wireless sensor network 2-nonintersecting paths routing algorithm of center calculation has been proposed, delay of response problem for center calculation mode to link-state change, adopt a kind of Adaptive Path maintenance mechanism of central dispatching, improved the flexibility of route maintenance; Packet only needs to carry path bit sequence, simultaneously without any control overhead.

For achieving the above object, technical scheme of the present invention is as follows:

A kind of wireless sensor network 2-nonintersecting paths routing algorithm of center calculation, it usings jumping figure and link-quality as tolerance, utilize the whole network information to calculate the near-optimization 2-node-disjoint paths from source node to sink node, then generate only comprise host node, auxiliary node and path bit sequence micro-routing table and under pass to each node; Its step is:

The first step, collector node neighbor information, creates and initialization adjacency matrix M _a, father node matrix M _f, logic gradient matrix M _n, path matrix M _pand path metric matrix M _pLQ; Wherein,

M _aaccording to this matrix of neighbor information initialization collecting, if node i is the neighbours of node j, the capable j column element of i of this matrix is the link quality values that node i arrives node j, if node i is not the neighbours of node j, and this element maximum 255;

M _fthis entry of a matrix element is all initialized as 255; Represent not have set membership between start node;

Logic gradient matrix M _nn * 1 matrix, n be in network except sink the number of all nodes; In matrix, element representation node, to the logic Grad of sink node, is initialized as maximum 255;

Path matrix M _pn * HTL matrix, n be in network except sink the number of all nodes; HTL allows maximum hop count in network, and the capable j column element of i representation node i is to j hop node in the path of sink node;

Path metric matrix M _pLQfor n * 1 matrix, n be in network except sink the number of all nodes;

Element in matrix is the path metric value that node i arrives sink node, according to this matrix of neighbor information initialization, if the neighbours that sink node is node i are initialized as node i to the link quality values of sink node, otherwise is initialized as 255;

Second step, calculates two nonintersecting paths; Utilize CCDMPR algorithm in overall father node matrix M _fon corresponding logic diagram, by greedy path trace algorithm, set up all nodes to the non-intersect main path of sink node, the down hop Competitive Algorithms that then uses band to keep out of the way set generates all nodes to the non-intersect bypass footpath of sink node;

The 3rd step, generation is based on Zhufu node, auxiliary father node to the micro-routing table mechanism with path bit sequence, and after the 2-of all nodes nonintersecting paths has calculated, sink node will calculate under the path generating pass to each node;

The 4th step, issues node path information to all nodes except sink node;

The 5th step, carries out the updating maintenance in path.

In the described first step, the process of collector node neighbor information is:

While also not setting up nonintersecting paths in network, network is with the mode collector node neighbor information that floods; Node in network is broadcast to packed neighbor information the neighbor node of oneself with broadcast mode, if node receives the rreq packet that other nodes Origineaddr sends, first according to Flag attribute and Seqnum determined property, whether receive this rreq packet, if received this rreq packet, abandoned this packet, if do not received, to other neighbor nodes except Origineaddr node, broadcast this rreq packet, effective like this avoiding occurs that loop reduces data redundancy in network; It is last until sink node receives rreq packet stops;

In network, set up nonintersecting paths, the rreq packet of node sends to sink node according to the optimal path of setting up, Sink node receives after rreq packet, resolve that this packet obtains neighbor node and corresponding link quality values sends to PC by serial ports, PC temporarily leaves neighbor information in the neighbor information table of database according to receiving packet.

In the described first step, overall father node matrix M _fprocess of establishing as follows:

1), by breadth-first search at M _aon be established to the logic gradient of sink node; The logic gradient of sink node is designated as 0, and the logic gradient of the node of sink node direct neighbor is set to 1, and the gradient of the node of the gradient node direct neighbor that is i is set to i+1, and search successively, until each node obtains logic gradient;

2) each non-leaf node is with from as root, and the neighbor node that the logic gradient of take is equal to or less than inherent logic gradient is set up a logic two-layer tree as direct son;

3) by corresponding storage of data structure in overall father node matrix M _fin, storage mode is: if node i belongs to and take the logic two-layer tree that node j is root, make (M _f) _ij=(M _a) _ij' otherwise (M _f) _ij=255.

In described second step, the generative process that non-intersect main path generates is:

Path metric matrix M _pLQ, M _pLQfor n * 1 matrix, n be in network except sink the number of all nodes, (M _pLQ) _irepresent that node i, to the PLQ value in the path of sink node, adopts greedy path trace algorithm to generate optimal path, and the LQ sum of all links that calculating path comprises simultaneously, be referred to as PLQ; The optimal path generating is stored in main path matrix as the main path of nonintersecting paths in, corresponding PLQ value is stored in path metric matrix M _pLQin,

$\mathrm{Trace}\_\mathrm{Greedy}(M_F,M_P^{\mathrm{Master}},M_{\mathrm{PLQ}})$

1) put S set={ L, 2,3 ... n}, puts (M _pLQ) ₀=0;

If (M _f) _i0<255, makes (M _pLQ) _i=(M _f) _i0, NEXT[i]=0, if (M _f) _i0=255, make (M _pLQ) _i=∞, NEXT[i]=-1.

2) make (M _pLQ) _j=min{ (M _pLQ) _i, i ∈ S}, S=S-{j}, then turn 4);

3) to all i ∈ S, if there is (M _f) _ji<255, makes (M _pLQ) _i=min{ (M _pLQ) _i, (M _pLQ) _j+ (M _f) _ji, NEXt[i]=j, then turn 2);

4) make k=2, $T={\left(M_P^{\mathrm{Master}}\right)}_{j1};$ $\mathrm{while}(T>0)\{k++;T=\mathrm{NEXT}[T];{\left(M_P^{\mathrm{Master}}\right)}_{\mathrm{jk}}=T\};$ If S be empty set algorithm finish, otherwise turn 3);

It is O (n to the time complexity of the optimum main path of sink node that this algorithm produces all nodes ²), and the running of algorithm guarantees that the path producing does not exist loop.

The generation method that described non-intersect bypass footpath generates is:

Adopt band to keep out of the way the down hop Competitive Algorithms of set, the time complexity that calculates the optimum bypass footpath of all nodes is O (n ²), each node selects the both candidate nodes of PLQ minimum as down hop the node competition comprising in all main paths, until arrive sink node; The node of all current bypasses footpath process is also added to AvoidSet,

① $\mathrm{NHC}\_\mathrm{NodeDisjoint}(M_F,M_P^{\mathrm{Master}},M_P^{\mathrm{Secondary}})$

The source node that is i for each index

1) put S set={ 1,2,3 ... n), will own add and keep out of the way set of node AvoidSet, then make S=S-AvoidSt, k=l, u=i.

2) make (M _pLQ) _v=min{ (M _pLQ) _l, l ∈ S and F _ul< 255}, order ${\left(M_P^{\mathrm{Secondary}}\right)}_{\mathrm{ik}}=v,S=S-\left\{v\right\}.$

3) if v=0, algorithm finishes, otherwise makes k=k+l, u=v, turns 2);

② $\mathrm{NHC}\_\mathrm{LinkDisjoint}(M_F,M_P^{\mathrm{Master}},M_P^{\mathrm{Secondary}})$

The source node that is i for each index

1) put S set={ 1,2,3 ... n}, to all order by limit <e, f> keeps out of the way link set AvoidSet to adding, and then makes k=1, u=i;

2) order order by limit <e, f> adds AvoidSet simultaneously;

3) if v=O, algorithm finishes, otherwise makes k=k+1, u=v, turns 2).

In described the 3rd step, micro-routing table comprises five territory: ID and represents the affiliated node identification of micro-routing table, the father node of Primary node territory storage present node on main path, the father node of Secondary node storage present node on bypass footpath, Primary path bit series territory storage main path bit sequence, Secondary path bit series storage bypass footpath bit sequence, each of bit sequence represents the father node selection of each jumping, with 0, represent Zhufu node, the auxiliary father node of 1 expression;

When source node is selected packet along main or bypass radially during the transmission of sink node, source node adds oneself master or bypass footpath bit sequence and sequence pointer at the packet head producing, initial time series pointer is 1, main or radially sink node transmission of bypass along it;

Intermediate node receives after packet, and first resolution data packet header, adds 1 by sequence pointer, and reads bit elements value in the path bit sequence of current sequence pointer indication, bit elements value be 0 o'clock to its Zhufu node transmission, be 1 o'clock to its auxiliary father node transmission.

In described the 4th step, the sink node of take issues the routing information of node successively as starting point according to the increase of the logic gradient of node, so long as receive the node of routing information, just set up stable network, even if also exist the node that does not receive routing information also can not affect the stabilizing local network of being set up by the node of the routing information receiving in global network;

PC calculates two nonintersecting paths according to neighbor information, and the reverse route that the routing information of node and base station are arrived to this node is packaged into rrep and is handed down to destination node.Rrep issues in process node and receives rrep and first judge that this node is destination node, is not that the reverse routing iinformation of depositing according to the array path in rrep continues to issue until arrive destination node.

In described the 5th step, when algorithm completes after the generation of nonintersecting paths, record the main path metric that each node arrives base station with auxiliary path metric value when base station is received the rreq packet of node transmission again, reuse algorithm and calculate path metric matrix M _pLQ, obtain the current main path metric of each node with auxiliary path metric value when path status meets formula (6) or formula (7), the path status of this node reaches update condition;

Wherein, formula (8), (9), (10), (11) are in order to calculate for front primary network main path link quality values, for front primary network bypass footpath link quality values, for the link quality values of current network main path, for link quality values, the λ in current network bypass footpath is local updating threshold value (λ >0), Δ PLQ ^masterbe taken as the link-quality increment of current network main path, △ PLQ ^master> λ shows to only have when link-quality reducing amount surpasses threshold value, just triggers and upgrades, and other situation is without renewal; △ PLQ ^secondarybe taken as the absolute value of current network bypass footpath link-quality increment, Δ LQ ^secondaty> λ represents that change in link quality amount is reducing amount or raising amount while surpassing threshold value, all will trigger maintenance; When the result calculating meets update condition, issue the routing information renewal network that upgrades all nodes,

${\mathrm{\&Delta;PLQ}}^{\mathrm{Master}}={\mathrm{PLQ}}_t^{\mathrm{Master}}-{\mathrm{PLQ}}_0^{\mathrm{Master}}>\mathrm{\&lambda;}---\left(6\right)$

Or ${\mathrm{\&Delta;PLQ}}^{\mathrm{Secondary}}=|{\mathrm{PLQ}}_t^{\mathrm{Secondary}}-{\mathrm{PLQ}}_0^{\mathrm{Secondary}}|>\mathrm{\&lambda;}---\left(7\right)$

${\mathrm{PLQ}}_0^{\mathrm{Master}}=\underset{K=1}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{LQ}}_0^{\mathrm{Master}}---\left(8\right)$

${\mathrm{PLQ}}_0^{\mathrm{Secondary}}=\underset{K=1}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{LQ}}_0^{\mathrm{Secondary}}---\left(9\right)$

${\mathrm{PLQ}}_t^{\mathrm{Master}}=\underset{K=1}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{LQ}}_t^{\mathrm{Master}}---\left(10\right)$

${\mathrm{PLQ}}_t^{\mathrm{Secondary}}=\underset{K=1}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{LQ}}_t^{\mathrm{Secondary}}---\left(11\right).$

The invention has the beneficial effects as follows:

The CCDMPR algorithm that adopts center calculation mode, algorithm can generate source node to near-optimization 2-node (link) nonintersecting paths of sink node, thereby can significantly reduce average path length, and improves the reliability in path.Micro-routing table that algorithm adopts can reduce storage and the communication overhead of node greatly; The adaptive route maintenance mechanism of central dispatching has significantly improved the flexibility of route maintenance; When data route, packet only needs to carry path bit sequence, without any control message expense.This algorithm is applicable to network topology more stable and the computing of sink node and the stronger application scenarios of storage capacity.

Accompanying drawing explanation

Fig. 1 a is the nested two-layer tree of logic;

Fig. 1 b is corresponding nested sets;

Fig. 2 is micro-routing table form;

Fig. 3 is data packet format and path bit sequence;

Fig. 4 is working-flow;

Fig. 5 is the network topology structure that floods;

Fig. 6 is nonintersecting paths algorithm flow chart;

Fig. 7 is for generating bit sequence flow chart;

Fig. 8 is node processing rrep packet flow process figure;

The data packet transmission success rate of the true experiment of Fig. 9.

Embodiment

Below in conjunction with accompanying drawing and embodiment, the present invention will be further described.

Operation principle of the present invention is as follows:

1. the collection of neighbor information

1.1 rreq data packet formats

Type type of data packet, value is RREQ_MSG

RREQ_ID rreq packet id, value is for producing the node number of the source node of rreq

The group number of Flag neighbor information, divides three groups to send this attribute can value be INFO_FIRST, INFO_SECOND, INFO_THIRD owing to being subject to network bandwidth limitations neighbor information.

Bit routing information bit value, path is set up rreq afterwards and is sent according to the optimal path of setting up according to this Bit value

Hopcnt is from source node to the jumping figure of processing the node of this rreq packet.

Origineaddr sends the node number of the node of rreq, in 1.2 joints flood transmission, can make referrals to

The sequence number of the current rreq of Seqnum can be introduced in 1.2 joints

First neighbor node number in Neighbor1 node neighbor information table.

The link quality values of Cost1 and neighbours Neighbor1

Neighbor and cost value thereof are the neighbor informations that sink node will be collected.

The collection of 1.2 rreq

While also not setting up nonintersecting paths in network, the network mode collector node neighbor information that flooded.Node in network is broadcast to packed neighbor information the neighbor node of oneself with broadcast mode, if node receives the rreq that other nodes (Origineaddr) send, first according to Flag attribute and Seqnum determined property, whether receive this rreq packet, if received this rreq packet, abandon this packet, if do not received, to other neighbor nodes except Origineaddr node, broadcast this rreq packet, can effectively avoid like this occurring that loop reduces data redundancy in network.It is last until sink node receives rreq packet stops.

In network, set up nonintersecting paths, the rreq packet of node sends to sink node Sink node according to the optimal path of setting up and receives after rreq packet, resolve that this packet obtains neighbor node and corresponding link quality values sends to PC by serial ports, PC temporarily leaves neighbor information in the neighbor information table of database according to receiving packet.

2. problem is described and model definition

Suppose that the link between node is bi-directional symmetrical, wireless sensor network can carry out abstract representation, the set that V is node, the set that E is wireless link with composing power non-directed graph G (V, E).The 2-nonintersecting paths to sink node from any sensor node S with the constraint of obedience formula (1) or (2).

2-node is non-intersect

$\&ForAll;v\&Element;V^{\&prime;}(v\&Element;P_{S-\mathrm{to}-\mathrm{Sink}}^{\mathrm{Master}}\&RightArrow;v\&NotElement;P_{S-\mathrm{to}-\mathrm{Sink}}^{\mathrm{Secondary}}),$ V=V-{S wherein, Sink} (1)

2-Link-disjoint paths

$\&ForAll;e\&Element;E(e\&Element;P_{S-\mathrm{to}-\mathrm{Sink}}^{\mathrm{Master}}\&RightArrow;e\&NotElement;P_{S-\mathrm{to}-\mathrm{Sink}}^{\mathrm{Secondary}})---\left(2\right)$

Define 1. adjacency matrix M _a, M _an * n matrix, n be in network except sink the number of all nodes, (M _a) _ijthe index that represents be the link-quality LQ (Link Quality) of the node of the i node that is j to index, the present invention supposes that node LQ can be by knowing someway, the span of LQ is 0-255, the less expression link-quality of LQ value is better.

Define 2. main path matrixes with bypass drive matrix with be n * HTL matrix, n be in network except sink the number of all nodes, HTL (hop-to-live) represents the maximum hop count allowing in network, represent that source node that index is i is to the j hop node on the main path of sink node, represent that source node that index is i is to the j hop node on the bypass footpath of sink node, or be 0 to show that this paths has arrived destination node (sink).

The center calculation model that the present invention adopts adopts adjacency matrix M _aas input parameter, disjoint main path matrix with bypass drive matrix as output parameter.Known according to formula (1) and formula (2), the nonintersecting paths constraint of center calculation model is converted into formula (3) and formula (4).

The constraint of 2-point nonintersecting paths:

$\&ForAll;i\&Element;\{\mathrm{1,2,3}\&CenterDot;\&CenterDot;\&CenterDot;n\}\&ForAll;p,q\&Element;\{\mathrm{1,2,3}\&CenterDot;\&CenterDot;\&CenterDot;\mathrm{HTL}\}$ (3)

2-Link-disjoint paths path constraint:

$\&ForAll;i\&Element;\{\mathrm{1,2,3}\&CenterDot;\&CenterDot;\&CenterDot;n\}\&ForAll;p,q\&Element;\{\mathrm{1,2,3}\&CenterDot;\&CenterDot;\&CenterDot;(\mathrm{HTL}-1)\}$ (4)

3.CCDMPR algorithm design

The running of CCDMPR algorithm is divided into four-stage: overall father node matrix is set up, and nonintersecting paths generates and passes down, data route, and Adaptive Path is safeguarded.

3.1 overall father node matrixes are set up

During netinit, first algorithm collects the LQ between neighbor table information, node and the neighbor node of all the sensors node by directed diffusion way, and deposits adjacency matrix M in _a.In order to prevent that the excessively poor path of link-quality from occurring, a threshold value η is set as a LQ threshold value here, the link that is greater than η (showing that link-quality is poor) will be rejected.Then, algorithm is at M _abasis on according to logic gradient, set up overall father node matrix M _f.

Define 3. overall father node matrix M _f, M _ffor n * n matrix, n be in network except sink the number of all nodes, if node i is for take the child node of the logic two-layer tree that node j is root, make (M _f) _ij=(M _a) _ij, otherwise (M _f) _ij=255.

The process of establishing of overall situation father node matrix is as follows: the first step, by breadth-first search at M _aon be established to the logic gradient of sink node.The logic gradient of sink node is designated as 0, and the logic gradient of the node of sink node direct neighbor is set to 1, and the gradient of the node of the gradient node direct neighbor that is i is set to i+l, and search successively, until each node obtains logic gradient; Second step, each non-leaf node is with from as root, and the neighbor node that the logic gradient of take is equal to or less than inherent logic gradient is set up a logic two-layer tree as direct son;

The 3rd step, by corresponding storage of data structure in overall father node matrix M _fin, storage mode is: if node i belongs to and take the logic two-layer tree that node j is root, make (M _f) _ij=(M _a) _ij' otherwise (M _f) _ij=255.

Logic illustration corresponding to overall situation father node matrix is for example shown in Fig. 1 (a), and its corresponding logic nested sets is as shown in Fig. 1 (b).

The foundation of overall situation father node matrix can be so that each sensor node adds many trees, for architecture is set up in the generation of 2-nonintersecting paths below, and the limit of wiping out some unnecessary limits simultaneously and likely producing loop.

3.2 nonintersecting paths generate

CCDMPR algorithm is in overall father node matrix M _fon corresponding logic diagram, by greedy path trace algorithm, set up all nodes to the non-intersect main path of sink node, the down hop Competitive Algorithms that then uses band to keep out of the way set generates all nodes to the non-intersect bypass footpath of sink node.

3.2.1 non-intersect main path generates

Define 4. path metric matrix M _pLQ, M _pLQfor n * 1 matrix, n be in network except sink the number of all nodes, (M _pLQ) _irepresent that node i is to the PLQ value in the path of sink node.

Algorithm adopts greedy path trace algorithm to generate optimal path, and the LQ sum of all links that calculating path comprises simultaneously, is referred to as PLQ (Path Link Quality).The optimal path generating is stored in main path matrix as the main path of nonintersecting paths in, corresponding PLQ value is stored in path metric matrix M _pLQin.Arthmetic statement is as follows:

$\mathrm{Trace}\_\mathrm{Greedy}(M_F,M_P^{\mathrm{Master}},M_{\mathrm{PLQ}})$

1) put S set={ 1,2,3 ... n}, puts (M _pLQ) ₀=0;

If (M _f) _i0<255, makes (M _pLQ) _i=(M _f) _i0, NEXT[i]=0, if (M _f) _i0=255, make (M _pLQ) _i=∞, NEXT[i]=-1.

2) make (M _pLQ) _j=min{ (M _pLQ) _i, i ∈ S}, S=S-{j}, then turn 4)

3) to all i ∈ S, if there is (M _f) _ji<255,

Make (M _pLQ) _i=min{ (M _pLQ) _i, (M _pLQ) _j+ (M _f) _ji, NEXT[i]=j, yet turn 2).

4) make k=2, $T={\left(M_P^{\mathrm{Master}}\right)}_{j1};$ $\mathrm{while}(T>0)\{k++;T=\mathrm{NEXT}[T];{\left(M_P^{\mathrm{Master}}\right)}_{\mathrm{jk}}=T\};$ If S be empty set algorithm finish, otherwise turn 3).

It is O (n to the time complexity of the optimum main path of sink node that this algorithm produces all nodes ²), and the running of algorithm guarantees that the path producing does not exist loop.

3.2.2 non-intersect bypass footpath generates

After the main path of nonintersecting paths generates, above-mentioned greedy algorithm acquisition can be applied afterwards again by deleting corresponding node (link) in the bypass footpath of nonintersecting paths, but this mode need to be carried out once full algorithm computing to each node, and the time complexity that calculates the non-intersect bypass footpath of all nodes reaches O (n ³), be not suitable for fairly large wireless sensor network.The present invention uses a kind of band to keep out of the way down hop competition (Next Hop Competing, NHC) algorithm of set, and this algorithm can obtain approximate optimal solution, and the time complexity that calculates the optimum bypass footpath of all nodes is O (n ²).Each node adds the node comprising in all main paths (link) to keep out of the way set A voidSet, all father nodes (link) that are not included in AvoidSet form both candidate nodes (link) collection, then by competition, select the both candidate nodes of PLQ minimum as down hop, until arrive sink node.The competition mechanism of NHC algorithm can not guarantee the appearance of loop, so algorithm is in running, and the node (link) of all current bypasses footpath process is also added to AvoidSet, and this mechanism can be avoided the appearance of loop effectively.

Being described below of NHC algorithm:

① $\mathrm{NHC}\_\mathrm{NodeDisjoint}(M_F,M_P^{\mathrm{Master}},M_P^{\mathrm{Secondary}})$

The source node that is i for each index

1) put S set={ 1,2,3 ... n}, will own add and keep out of the way set of node AvoidSet, then make S=S-AvoidSt, k=1, u=i.

2) make (M _pLQ) _v=min{ (M _pLQ) _l, l ∈ S and F _ul< 255}, order ${\left(M_P^{\mathrm{Secondary}}\right)}_{\mathrm{ik}}=v,S=S-\left\{v\right\}.$

3) if v=0, algorithm finishes, otherwise makes k=k+1, u=v, turns 2).

② $\mathrm{NHC}\_\mathrm{LinkDisjoint}(M_F,M_P^{\mathrm{Master}},M_P^{\mathrm{Secondary}})$

The source node that is i for each index

1) put S set={ 1,2,3 ... n), to all , order by limit <e, f> keeps out of the way link set AvoidSet to adding, and then makes k=1, u=i.

2) order order , by limit <e, f> adds AvoidSet. simultaneously

3) if v=0, algorithm finishes, otherwise makes k=k+1, u=v, turns 2).

3.3 micro-routing tables and data route

After the 2-of all nodes nonintersecting paths has calculated, sink node passes to each node by calculating under the path generating.Consider that complete routing table is larger, pass down and will bring very large communication overhead, the limited storage space of while sensor node own, so the scheme that whole routing table passes is down infeasible.The present invention has designed a kind of based on < Zhufu node, and auxiliary father node > is to the micro-routing table mechanism with path bit sequence, and micro-route tableau format as shown in Figure 2.

This micro-routing table comprises five territory: ID and represents the affiliated node identification of micro-routing table, the father node of Primary node territory storage present node on main path, the father node of Secondary node storage present node on bypass footpath, Primar path bit series territory storage main path bit sequence (for example: 00000000), Secondary path bit series storage bypass footpath bit sequence (for example: 01010010), each of bit sequence represents the father node selection (0 represents Zhufu node, and 1 represents auxiliary father node) of each jumping.Adopt the benefit of path bit sequence to be, each jumping in micro-routing table all only takies a bit, can greatly reduce the size of routing table, thereby saves communication and storage overhead.

When source node selects packet to transmit along master (auxiliary) path to sink node, source node adds oneself master (auxiliary) path bit sequence and sequence pointer (initial time series pointer is 1) at the packet head producing, along its main (auxiliary) path, to sink node, transmit.The data packet format that source node produces as shown in Figure 3.

Wherein, Path flag is path sign, and Path flag=0 represents main path, and Path flag=1 represents bypass footpath; Series pointer is sequence pointer, is used to indicate the current bit position in sequence; Pathbit series is entrained bit sequence; LQ is the LQ currency that source node arrives main (auxiliary) father node, is mainly used in route maintenance.

Intermediate node receives after packet, and first resolution data packet header, adds 1 by sequence pointer, and reads bit elements value in the path bit sequence of current sequence pointer indication, bit elements value be 0 o'clock to its Zhufu node transmission, be 1 o'clock to its auxiliary father node transmission.Adopt this routing policy, when there is failure node (link), data only need just can effectively be avoided failure node (link) along the auxiliary path transmission of present node, do not resend, thereby save communication overhead and do not need to date back to source node when improving reliability.

4.. routing information issues

4.1 routing information packet rrep data packet formats

Type

Path

Pri_parent

Pri_bit

Sec_parent

Sec_bit

Destiaddr

Seqnum

Type type of data packet RREP_MSG

Path node array, oppositely routed path node

Pri_parent Zhufu node node number

The bit sequence of Pri_bit main path

The auxiliary father node node number of Sec_parent

The bit sequence in Sec_bit bypass footpath

Destiaddr destination node address, the node number of the node that routing information will send to

The sequence number of Seqnum rrep

4.2 routing information packet rrep issue

4.2.1 determine routing information transmitting sequence

The sink node of take can be set up stabilizing network as shown in the figure more fast as the routing information that starting point issues node successively according to the increase of the logic gradient of node, so long as receive the node of routing information, just can set up stable network, even if also there is the node that does not receive routing information in global network, also can not affect the stabilizing local network of being set up by the node of the routing information receiving.

4.2.2 oppositely route sends rrep packet

PC calculates two nonintersecting paths according to neighbor information, and the reverse route that the routing information of node and base station are arrived to this node is packaged into rrep and is handed down to destination node.Rrep issues in process node and receives rrep and first judge that this node is destination node, is not that the reverse routing iinformation of depositing according to the array path in rrep continues to issue until arrive destination node.

5. the maintenance update in path

5.1 update condition

When algorithm completes after the generation of nonintersecting paths, record the main path metric that each node arrives base station with auxiliary path metric value when base station is received the rreq packet of node transmission again, reuse algorithm and calculate path metric matrix M _pLQ, obtain the current main path metric of each node with auxiliary path metric value when path status meets formula (6) or formula (7), the path status of this node reaches update condition.Wherein, formula (8), (9), (10), (11) are in order to calculate for front primary network main path link quality values, for front primary network bypass footpath link quality values, for the link quality values of current network main path, for link quality values, the λ in current network bypass footpath is local updating threshold value (λ >0), △ PLQ ^masterbe taken as the link-quality increment of current network main path, △ PLQ ^master> λ shows to only have when link-quality reducing amount surpasses threshold value, just triggers and upgrades, and other situation is without renewal.△ PLQ ^secondarybe taken as the absolute value of current network bypass footpath link-quality increment, Δ LQ ^secondarywhen > λ represents that change in link quality amount (reducing amount or raising amount) surpasses threshold value, all to trigger maintenance.When the result calculating meets update condition, issue the routing information renewal network that upgrades all nodes.

${\mathrm{\&Delta;PLQ}}^{\mathrm{Master}}={\mathrm{PLQ}}_t^{\mathrm{Master}}-{\mathrm{PLQ}}_0^{\mathrm{Master}}>\mathrm{\&lambda;}---\left(6\right)$

Or ${\mathrm{\&Delta;PLQ}}^{\mathrm{Secondary}}=|{\mathrm{PLQ}}_t^{\mathrm{Secondary}}-{\mathrm{PLQ}}_0^{\mathrm{Secondary}}|>\mathrm{\&lambda;}---\left(7\right)$

${\mathrm{PLQ}}_0^{\mathrm{Master}}=\underset{K=1}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{LQ}}_0^{\mathrm{Master}}---\left(8\right)$

${\mathrm{PLQ}}_0^{\mathrm{Secondary}}=\underset{K=1}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{LQ}}_0^{\mathrm{Secondary}}---\left(9\right)$

${\mathrm{PLQ}}_t^{\mathrm{Master}}=\underset{K=1}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{LQ}}_t^{\mathrm{Master}}---\left(10\right)$

${\mathrm{PLQ}}_t^{\mathrm{Secondary}}=\underset{K=1}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{LQ}}_t^{\mathrm{Secondary}}---\left(11\right)$

Truly experiment Ministry of environment is deployed in the corridor of 2 to 5 layers of an office building, and all nodes are uniformly distributed relatively, and sink node is positioned at the center in 4th floors corridors.The node that experiment is used is mainly comprised of two parts: the radio frequency chip CC2420 of MSP430F5438 and TI, operating system adopts Multi-task real-time system FreeRTOS.

For convenience of experiment, applicant has adopted a upper computer software based on C++, for the calculating of nonintersecting paths and according to the sequence number statistics transmission success rate of the packet receiving.In network, all nodes are every 1 second to sink node transmission image data, and transmitting procedure does not adopt ACK retransmission mechanism equally, and sink node is given upper computer software processing after receiving data.In experiment, we compare CCDMR algorithm and classical distributed single path routing algorithm-minimum jump algorithm.The data packet number that we collect that respectively sink node successfully receives is 100,200,300,400,500 o'clock data transmission success, as shown in Figure 9.

As we know from the figure, in the situation that not adopting ACK retransmission mechanism, than jete single path algorithm, there is higher path transmission success rate in main path and bypass footpath that CCDMPR algorithm generates, and the transmission success rate of main path can reach more than 65%.Use at the same time in the situation of 2-nonintersecting paths, the path transmission success rate of packet can reach more than 75%, and the stability of path transmission also improves simultaneously.

Although above-mentioned, by reference to the accompanying drawings the specific embodiment of the present invention is described; but be not limiting the scope of the invention; one of ordinary skill in the art should be understood that; on the basis of technical scheme of the present invention, those skilled in the art do not need to pay various modifications that creative work can make or distortion still in protection scope of the present invention.

Claims (8)

1. the wireless sensor network 2-nonintersecting paths routing algorithm of a center calculation, it is characterized in that, it usings jumping figure and link-quality as tolerance, utilize the whole network information to calculate the near-optimization 2-node-disjoint paths from source node to sink node, then generate only comprise host node, auxiliary node and path bit sequence micro-routing table and under pass to each node; Its step is:

The first step, collector node neighbor information, creates and initialization adjacency matrix M _a, father node matrix M _f, logic gradient matrix M _n, path matrix M _pand path metric matrix M _pLQ; Wherein,

M _aaccording to this matrix of neighbor information initialization collecting, if node i is the neighbours of node j, the capable j column element of i of this matrix is the link quality values that node i arrives node j, if node i is not the neighbours of node j, the maximum occurrences that this element allows is 255;

M _fthis entry of a matrix element is all initialized as 255; Represent not have set membership between start node;

Logic gradient matrix M _nn * 1 matrix, n be in network except sink the number of all nodes; In matrix, element representation node, to the logic Grad of sink node, is initialized as maximum 255;

Path matrix M _pn * HTL matrix, n be in network except sink the number of all nodes; HTL allows maximum hop count in network, and the capable j column element of i representation node i is to j hop node in the path of sink node;

Path metric matrix M _pLQfor n * 1 matrix, n be in network except sink the number of all nodes;

Element in matrix is the path metric value that node i arrives sink node, according to this matrix of neighbor information initialization, if the neighbours that sink node is node i are initialized as node i to the link quality values of sink node, otherwise is initialized as 255;

Second step, calculates two nonintersecting paths; Utilize the disjoint multiple paths route CCDMPR algorithm of center calculation in overall father node matrix M _fon corresponding logic diagram, by greedy path trace algorithm, set up all nodes to the non-intersect main path of sink node, the down hop Competitive Algorithms that then uses band to keep out of the way set generates all nodes to the non-intersect bypass footpath of sink node;

The 3rd step, generation is based on Zhufu node, auxiliary father node to the micro-routing table mechanism with path bit sequence, and after the 2-of all nodes nonintersecting paths has calculated, sink node will calculate under the path generating pass to each node;

The 4th step, issues node path information to all nodes except sink node;

The 5th step, carries out the updating maintenance in path.

2. the wireless sensor network 2-nonintersecting paths routing algorithm of center calculation as claimed in claim 1, is characterized in that, in the described first step, the process of collector node neighbor information is:

While also not setting up nonintersecting paths in network, the network mode collector node neighbor information that flooded; Node in network is broadcast to packed neighbor information the neighbor node of oneself with broadcast mode, if node receives the rreq packet that other nodes Origineaddr sends, first according to Flag attribute and Seqnum determined property, whether receive this rreq packet, if received this rreq packet, abandoned this packet, if do not received, to other neighbor nodes except Origineaddr node, broadcast this rreq packet, avoid like this occurring reducing data redundancy by loop in network; It is last until sink node receives rreq packet stops;

In network, set up nonintersecting paths, the rreq packet of node sends to sink node according to the optimal path of setting up, Sink node receives after rreq packet, resolve that this packet obtains neighbor node and corresponding link quality values sends to PC by serial ports, PC temporarily leaves neighbor information in the neighbor information table of database according to receiving packet.

3. the wireless sensor network 2-nonintersecting paths routing algorithm of center calculation as claimed in claim 1, is characterized in that, in the described first step, and overall father node matrix M _fprocess of establishing as follows:

1) by breadth-first search at M _aon be established to the logic gradient of sink node; The logic gradient of sink node is designated as 0, and the logic gradient of the node of sink node direct neighbor is set to 1, and the gradient of the node of the gradient node direct neighbor that is i is set to i+1, and search successively, until each node obtains logic gradient;

2) each non-leaf node is with from as root, and the neighbor node that the logic gradient of take is equal to or less than inherent logic gradient is set up a logic two-layer tree as direct son;

3) by corresponding storage of data structure in overall father node matrix M _fin, storage mode is: if node i belongs to and take the logic two-layer tree that node j is root, make (M _f) _ij=(M _a) _ij, otherwise (M _f) _ij=255, (M _a) _ijrepresent that index is the link-quality LQ of the node of the i node that is j to index.

4. the wireless sensor network 2-nonintersecting paths routing algorithm of center calculation as claimed in claim 1, is characterized in that, in described second step, the generative process that non-intersect main path generates is:

Path metric matrix M _pLQ, M _pLQfor n * 1 matrix, n be in network except sink the number of all nodes, (M _pLQ) _irepresent that node i, to the PLQ value in the path of sink node, adopts greedy path trace algorithm to generate optimal path, and the link-quality LQ sum of all links that calculating path comprises simultaneously, be referred to as PLQ; The optimal path generating is stored in main path matrix as the main path of nonintersecting paths in, corresponding PLQ value is stored in path metric matrix M _pLQin,

$\mathrm{Trace}\_\mathrm{Greedy}(M_F,M_P^{\mathrm{Master}},M_{\mathrm{PLQ}})$

9) put S set={ 1,2,3 ... n}, puts (M _pLQ) ₀=0; If (M _f) _i0< 255, make (M _pLQ) _i=(M _f) _i0, NEXT[i]=0, if (M _f) _i0=255, make (M _pLQ) _i=∞, NEXT[i]=-1.

10) make (M _pLQ) _j=min{ (M _pLQ) _i, i ∈ S}, S=S-{j}, then turn 4);

11) to all i ∈ S, if there is (M _f) _ji< 255, make (M _pLQ) _i=min{ (M _pLQ) _i, (M _pLQ) _j+ (M _f) _ji, NEXT[i]=j, then turn 2);

12) order while (T > 0) { k++; T=NEXT[T]; if S be empty set algorithm finish, otherwise turn 3);

It is O (n to the time complexity of the optimum main path of sink node that this algorithm produces all nodes ²), and the running of algorithm guarantees that the path producing does not exist loop.

5. the wireless sensor network 2-nonintersecting paths routing algorithm of center calculation as claimed in claim 1, is characterized in that, the generation method that described non-intersect bypass footpath generates is:

Adopt band to keep out of the way the down hop Competitive Algorithms of set, the time complexity that calculates the optimum bypass footpath of all nodes is O (n ²), each node selects the both candidate nodes of PLQ minimum as down hop the node competition comprising in all main paths, until arrive sink node; The node of all current bypasses footpath process is also added to AvoidSet,

①NHC_NodeDisjoint(M _F, )

The source node that is i for each index

1) put S set={ 1,2,3 ... n}, will own add and keep out of the way set of node AvoidSet, then make S=S-AvoidS, k=1, u=i.

2) make (M _pLQ) _v=min{ (M _pLQ) _l, l ∈ S and F _ul< 255}, order s=S-{v}.

3) if v=0, algorithm finishes, otherwise makes k=k+1, u=v, turns 2);

②NHC_LinkDisjoint(M _F, )

The source node that is i for each index

1) put S set={ 1,2,3 ... n}, to all ${\left(M_P^{\mathrm{Master}}\right)}_{\mathrm{ij}}>0,$ Order $e={\left(M_P^{\mathrm{Master}}\right)}_{\mathrm{ij}},f={\left(M_P^{\mathrm{Master}}\right)}_{i(j+1)},$ By limit < e, f > keeps out of the way link set AvoidSet to adding, and then makes k=1, u=i;

2) make (M _pLQ) _v=min{ (M _pLQ) _l, l ∈ S and F _ul< 255 and order by limit < e, f > adds AvoidSet simultaneously;

3) if v=0, algorithm finishes, otherwise makes k=k+1, u=v, turns 2).

6. the wireless sensor network 2-nonintersecting paths routing algorithm of center calculation as claimed in claim 1, it is characterized in that, in described the 3rd step, micro-routing table comprises five territory: ID and represents the affiliated node identification of micro-routing table, the father node of Primary node territory storage present node on main path, the father node of Secondary node storage present node on bypass footpath, Primary path bit series territory storage main path bit sequence, Secondary path bit series storage bypass footpath bit sequence, each of bit sequence represents the father node selection of each jumping, with 0, represent Zhufu node, 1 represents auxiliary father node,

When source node is selected packet along main or bypass radially during the transmission of sink node, source node adds oneself master or bypass footpath bit sequence and sequence pointer at the packet head producing, initial time series pointer is 1, main or radially sink node transmission of bypass along it;

Intermediate node receives after packet, and first resolution data packet header, adds 1 by sequence pointer, and reads bit elements value in the path bit sequence of current sequence pointer indication, bit elements value be 0 o'clock to its Zhufu node transmission, be 1 o'clock to its auxiliary father node transmission.

7. the wireless sensor network 2-nonintersecting paths routing algorithm of center calculation as claimed in claim 1, it is characterized in that, in described the 4th step, the sink node of take issues the routing information of node successively as starting point according to the increase of the logic gradient of node, so long as receive the node of routing information, just set up stable network, even if also exist the node that does not receive routing information also can not affect the stabilizing local network of being set up by the node of the routing information receiving in global network;

PC calculates two nonintersecting paths according to neighbor information, and the reverse route that the routing information of node and base station are arrived to this node is packaged into rrep and is handed down to destination node; Rrep issues in process node and receives rrep and first judge that this node is destination node, is not that the reverse routing iinformation of depositing according to the array path in rrep continues to issue until arrive destination node.

8. the wireless sensor network 2-nonintersecting paths routing algorithm of center calculation as claimed in claim 1, is characterized in that, in described the 5th step, when algorithm completes after the generation of nonintersecting paths, records the main path metric that each node arrives base station with auxiliary path metric value when base station is received the rreq packet of node transmission again, reuse algorithm and calculate path metric matrix M _pLQ, obtain the current main path metric of each node with auxiliary path metric value when path status meets formula (6) or formula (7), the path status of this node reaches update condition;

Wherein, formula (8), (9), (10), (11) are in order to calculate for front primary network main path link quality values, for front primary network bypass footpath link quality values, for the link quality values of current network main path, for link quality values, the λ in current network bypass footpath is local updating threshold value (λ >0), Δ PLQ ^masterbe taken as the link-quality increment of current network main path, Δ PLQ ^master> λ shows to only have when link-quality reducing amount surpasses threshold value, just triggers and upgrades, and other situation is without renewal; Δ PLQ ^secondarybe taken as the absolute value of current network bypass footpath link-quality increment, Δ LQ ^secondary> λ represents that change in link quality amount is reducing amount or raising amount while surpassing threshold value, all will trigger maintenance; When the result calculating meets update condition, issue the routing information renewal network that upgrades all nodes,

${\mathrm{\&Delta;PLQ}}^{\mathrm{Master}}={\mathrm{PLQ}}_t^{\mathrm{Master}}-{\mathrm{PLQ}}_0^{\mathrm{Master}}>\mathrm{\&lambda;}---\left(6\right)$

Or ${\mathrm{\&Delta;PLQ}}^{\mathrm{Secondary}}=\left|{\mathrm{PLQ}}_t^{\mathrm{Secondary}}{-\mathrm{PLQ}}_0^{\mathrm{Secondary}}\right|>\mathrm{\&lambda;}---\left(7\right)$

${\mathrm{PLQ}}_0^{\mathrm{Master}}=\underset{K=1}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{LQ}}_0^{\mathrm{Master}}---\left(8\right)$

${\mathrm{PLQ}}_0^{\mathrm{Secondary}}=\underset{K=1}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{LQ}}_0^{\mathrm{Secondary}}---\left(9\right)$

${\mathrm{PLQ}}_t^{\mathrm{Master}}=\underset{K=1}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{LQ}}_t^{\mathrm{Master}}---\left(10\right)$

${\mathrm{PLQ}}_t^{\mathrm{Secondary}}=\underset{K=1}{\overset{N}{\mathrm{\&Sigma;}}}{\mathrm{LQ}}_t^{\mathrm{Secondary}}---\left(11\right).$