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Hindawi Publishing CorporationJournal of SensorsVolume 2013 Article ID 625274 9 pageshttpdxdoiorg1011552013625274

Research ArticleLink Expiration Time-Aware Routing Protocol for UWSNs

Md Ashraf Uddin1 and Mamun-or-Rashid2

1Department of Computer Science and Engineering Mawlana Bhashani Science and Technology University Tangail 1902 Bangladesh2Department of Computer Science and Engineering University of Dhaka Dhaka 1000 Bangladesh

Correspondence should be addressed to Md Ashraf Uddin ashraf 16cseduyahoocom

Received 11 October 2012 Accepted 9 January 2013

Academic Editor Ignacio Matias

Copyright copy 2013 Md A Uddin and Mamun-or-Rashid This is an open access article distributed under the Creative CommonsAttribution License which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

We propose a link expiration time-aware routing protocol for UWSNs In this protocol a sending node forwards a data packet afterbeing sure that the packet reaches the forwarding node and acknowledgment is returned to the sending node after receiving the datapacket Node mobility is handled in the protocol through the calculation of the link expiration time and sending the packet basedon the link expiration time Although the protocol employs two types of control packet it provides less energy consumption and atthe same time is providing better reliability of packets reaching to the destination because of using acknowledgement packet Theforwarding decision of node is taken by applying Bayesrsquo uncertainty theoremWe use depth residual energy and distance from theforwarding node to the sending node as evidence in Bayesrsquo theorem In this protocol we use the concept of expert systems rankingpotentially true hypothesis Extensive simulation has been executed to endorse better performance of the proposed protocol

1 Introduction

About seventy percentage of the Earth is covered by waterThis huge area is continuously being explored with a viewto discover hidden knowledge and unknown resources Theresearch underwater is being accomplished for the purpose ofmany kinds of application such as ocean sampling networksenvironmental monitoring undersea explorations disasterprevention and mine reconnaissance [1ndash3] Underwater sen-sor network has appeared as a new dimension that helps ininvestigating the vast area under water and provides vitalinformation to the surface One of the imperative sections ofunderwater sensor network is tomature the routing protocolsthat are already existent and to revamp the routing protocolfor UWSNs In order to develop the routing protocol forUWSNs some concerns pertaining to sensor networks haveto be considered UWSNs have to face some challenges suchas node mobility limited battery limited bandwidth andmultipath noise InUWSNs the nodemoves with the velocityof 3ndash6 kmh [4] because of the water current So it is notpossible to progress routing protocols which work with thewhole topology Moreover underwater sensor node cannotbe recharged or changed because of the harsh underwaterenvironment Underwater sensor node uses an acoustic

modem whose propagation speed is 1500ms [5] to transferdata to each other Our proposed routing protocol is devisedby cogitating upon limited battery and limited bandwidthOur proposed routing protocol provides shorter end-to-enddelay and evades control packet to guide data packet to thedestination entirely which hoards up huge amount of totalenergy Information of control packet is incorporated in thedata packet

The rest of this paper is organized as follows We describerelated works in Section 2 Our proposed link expiration timeaware routing protocol for UWSNs is presented in Section 3and the simulation results are presented in Section 4 Finallywe conclude the paper in Section 5 along with future researchdirection

2 Related Works

One of the primary topics for any network is routingand routing protocols are regarded as an indictment ofdetermining and preserving the routes Most of the researchworks pertaining to underwater sensor networks have beenon the issues related to the physical layer On the otherhand routing techniques are a comparatively new arena ofthe network layer of UWSNs Thus providing an efficient

2 Journal of Sensors

routing algorithm becomes a significant mission Althoughunderwater acoustic network has continued to be studied fordecades underwater networking and routing protocols arestill at the infant stage of research We have studied somerouting protocols to shape our own routing protocol

Vector-based forwarding (VBF) [5] guides the packetfrom the source to the destination Packets are forwarded onlyby those sensor nodes that arewithin the range119877of the vectorThe forwarding process of VBF is thought to be a routingpipe (virtual pipe) between the source and the destinationnodes The energy of the network is saved because only thenodes that come across the forwarding path are involvedin packet routing It provides small data delivery ratio insparse networks Moreover delivery ratio decreases whennodes are mobile and is sensitive to the routing pipersquos radiusHigh communication time in dense network is needed andmultiple nodes act as relay nodes

To reduce the high communication time and to handlenode mobility VBF routing protocol has been modified andproposed a hop-by-hop VBF (HH-VBF) [6] routing protocolThis protocol forms the routing pipe in a hop-by-hop fashionenhancing the packet delivery ratio significantly It does notuse a single virtual pipe and each node forwards packetbased on its current location When a node receives a packetit first holds the packet for sometime Each node in theneighborhood may hear the same packet multiple timesEach nodersquos overhearing the duplicate packet transmissionto control the forwarding of this packet is allowed in HH-VBF routing protocol In sparse networks HH-VBF candiscover a data delivery path as long as there exists one in thenetwork It also suffers from some disadvantages such as longpropagation delay high energy cost in dense networks andbeing not efficient enough with node mobility

In sector-based routing with destination location predic-tion [7] a node knows its own location and predicts thelocation of the destination node where the precise knowledgeof the destinationrsquos location is relaxed by it The senderdetermines its next hop using information received fromthe candidate nodes It eliminates the problem of havingmultiple nodes acting as relay nodes It does not require torebroadcast the request to send (RTS) every time it cannotfind a candidate node within its transmitting range In SBR-DLP node speed causes disconnections and it gives relativelylow PDR in sparse networks and has relatively high energyconsumption in dense networks where it performs best butbetter packet delivery ratio when all nodes are mobile

Distributed underwater clustering scheme (DUCS) [8]is an adaptive self-organizing protocol that forms clustersIt is considered that there are always data to be sent tothe sink by the underwater sensor nodes and that powercontrol can be used to adjust its transmission power Ittries to be adapted to the intrinsic properties of underwaterenvironments and uses a continually adjusted timing advancecombined with guard time values to minimize data loss andmaintain communication quality Nodes are organized intolocal clusters One node is selected as a cluster head foreach cluster All data coming from noncluster head nodes aretransmitted to their cluster head via a single hop Data arereceived by the cluster-head node and transmitted to the sink

(via the relays of other cluster heads) using multihop routingDUCS incorporates randomized rotation of the cluster headamong the sensors to avoid draining the battery of anyunderwater sensor in the network As the number of thenodes decrease in the network a slight decrease occurs in thenumber of data messages packet delivery ratio

Multipath routing [9] is energy-efficient networks andovercomes long propagation delay and adverse link condi-tions Depending on how the routes are selected there is astrong likelihood of contention occurring among nodes thatare on different routes but close to one another The localsink connections are assumed to be via high-speed linksbeing wired to a buoy on the surface equipped with RFcommunications link or an undersea high-speed optical fiberThe ultimate goal of the underwater network is to ensure thatdata are delivered to one or more of these local sinks whichcollectively form a virtual sink Connection is establishedthrough wire or optical fiber Backup routes are created bydeploying redundant nodes Contention occurs among nodesdue to redundancy

In H2-DAB [10] sink node broadcasts a hello packet andthe sensor node that receives the packet is assigned a HopID by incrementing the Hop ID existing in the hello packetof sink node The packet-receiving node broadcasts the hellopacket after updating the Hop ID of the received hello packetIn this way sensor nodes are given a unique address from sinknodes to source node When the packet is forwarded to thesink node it searches for the sensor nodes with the smallestHop ID To forward a packet this protocol utilizes only thehop count which is not a good indicator to forward packetbecause UWSN is an energy-constrained network It does notguarantee the network living time because the same node canbe chosen again and again to transfer a packet Moreover inthis protocol inquiry request and inquiry reply packets are tobe exploited at the time of the forwarding of the data packetswhich is costly in terms of delay and energy

Depth-based routing (DBR) protocol [11] is an underwa-ter sensor network routing protocol which is based on thedepth information of each sensor In this routing protocolno complete dimensional information of the location of thesensor nodes is required and it can manage a dynamic net-work InDBR to deliver a packet it determines that the closerto the destination the smaller the depth of the forwardingnodes and to receive a packet it compares between the depthretrieving of the previous hop and its receiving nodersquos depthfor the qualified candidates to forward the packet DBR hasgood energy efficiency but not somuch good performance forthe dense network where it has significant end-to-end delayand high total energy consumption

All of these discussed routing protocols for UWSNs areefficient and effective in their own ways In this paper wehave developed a routing protocol to overcome the disad-vantages of the vector-based routing protocol [11] In DBRthe forwarding node takes the decision of packet forwardingbased on only the depth which can make more forwardingnodes compatible to forward a packet because of the nodersquossame depth We introduce a novel technique by consideringBayesrsquo theorem to assess the target node In our forwardingtechnique we use depth residual energy and the distance

Journal of Sensors 3

from the forwarding node to the sending node as evidenceWe calculate the link expiration time to handle nodemobilitybetween the two nodes

3 The Link Expiration TimeAware Routing Protocol

In this section we present our link expiration time aware(LETA) routing protocol in detail multiple-sink underwatersensor network architecture has been applied in the proposedrouting protocol In this section we have discussed aboutnetwork architecture protocol overview and protocol designFinally we present the algorithm of the proposed routingprotocol

31 The Network Architecture It is pointed out before thatthe multiple-sink underwater sensor network architecture[12] can be used by the proposed routing protocol the linkexpiration time aware (LETA) routing protocol Like DBR[11] it also takes advantages of the multiple-sink underwatersensor network architecture An example of such networks isdemonstrated in Figure 1 In this multiple-sink network thewater surface nodes that are called sink nodes are equippedwith the modem that is capable of capturing both radiofrequency and acoustic signal The nodes that send andreceive only acoustic signal are deployed in the underwa-ter environment Underwater sensor nodes with acousticmodems are placed in the interested 3D area and each one ofsuch nodes is assumed likely to be a data source Underwateracoustic nodes can accumulate data and also assist to conveydata to the sinks When a sink node receives a packet froman underwater acoustic node the sink node can conversewith each other efficiently via radio channels The protocolattempts to send a packet to any sink nodes on the surfacebecause if a surface node receives a packet it can send thepacket to other sinks or remote data centers quickly due tothe speed of radio frequency (with a propagation speed of3 times 10

8ms in air) which is five orders of magnitude higherthan sound propagation (at the speed of 15 times 10

3ms inwater) [5] Here the protocol does not pay attention to thecommunication between the surface nodes Instead it triesto transmit a packet to a fixed surface sink and assumes thatthe packet reaches to its destination The protocol has beenbuilt by considering the fact that every node knows its depthwhich is the vertical distance from the nodersquos position to thesurface and its position

32 Overview of the Proposed Routing Protocol Theproposedprotocol is divided into three phases named as selection ofcompatible forwarding node phase routing table formationphase by the sending node and target node selection phaseby the sending node to send data packet Each of these partsis discussed in this section

321 Selection of Compatible Forwarding Node Phase In thisphase most of the procedures are performed by the for-warding node The sending node broadcasts a hello messagenamed RREQ to discover its one-hop compatible forwarding

Water surface

Radio signals

Acoustic signals

Sink node

Sensor node

Figure 1 Multiple-sink underwater sensor network architecture

nodeUpon receiving theRREQmessage of the sending nodethe forwarding node estimates the probability of packet for-warding and packet discarding based on the depth differenceof the forwarding node and the sending node residual energyand the distance from the forwarding node to the sendingnode If the probability of packet forwarding is greater thanthat of packet discarding the forwarding node responds tothe sending node through RREP message incorporated itsprobability in the reply message

322 Routing Table Formation Phase After receiving RREPmessage from one-hop neighbor node the sending nodereckons the link expiration time with each compatible for-warding node The sending node keeps the forwarding nodein its routing table according to the decreasing order of theforwarding nodesrsquo probability which means that the nodewith the highest probability is at the first position in therouting table and that the next highest is at the secondposition

323 Target Node Selection Phase After completing theformation of the routing table the sending node picksup the forwarding node with the highest probability andcorresponding to the link expiration time of the forwardingtime in order to handle node mobility The link expirationtime is compared with the time to reach the packet to theforwarding node and return acknowledgment to the sendingnode from the forwarding node If the link expiration time ofthe forwarding node exceeds the packetrsquos reaching time andthe acknowledgmentrsquos receiving time then the forwardingnode is chosen as a target node and the packet is forwarded


Table 1 Route request message format

Sender ID Senderrsquos location Depth

Table 2 Route reply message format

Forwarding node ID Probability

Table 3 Data packet format

Sender ID Packet sequence number Data

to the node Otherwise another node is chosen in the sameway If no node in the routing table is found as target nodethen routing table is formed anew

33 Protocol Design Protocol design takes into accountthe packet format used by the proposed protocol and theestimation of nodersquos forwarding probability is performed inthis section The link expiration time for the forwardingnodes is estimated and finally the proposed routing protocolalgorithm is presented

331 Packet Format Two kinds of packets [13] are intro-duced in this protocol Firstly the sending node broadcastsa control packet named route request (RREQ) message to itsneighbor within transmission range 119877 in order to inform itsneighbor of its location and depthThe route request messageincorporates the sending nodersquos ID location and depth thatare used by the forwarding node to calculate its forwardingprobability The packet format of RREQ is illustrated inTable 1

Other control packets include RREP message whichcarries the information of the forwarding nodersquos probabilityto forward the packet and ACK which is used to confirm thepacket received by the forwarding node The RREP messageis illustrated in Table 2

Secondly data packet is demonstrated in Table 3 Thepacket header consists of two fields sender ID and packetsequence number and data ldquoSender IDrdquo is the identifier of thesource node ldquoPacket sequence numberrdquo represents a uniquesequence number that is assigned by the source node tothe packet Packet sequence number together with senderID is required to differentiate between packets in later dataforwarding

332 Estimation of Nodersquos Forwarding Probability In thissection we have calculated the probability of forwardingpacket and discarding packet of a node based on depthresidual energy and distance from the forwarding node to thesending node In order to calculate the probability we use theBayesian reasoning We assume that the packet forwardingand packet discarding are two hypotheses and three linesof observing evidence are the depth difference between thesending node and the forwarding node the difference ofcurrent residual energy and the threshold residual energy ofthe forwarding node and the distance from the sending nodeto the forwarding node

Let1198671= packet forwarding119867

2= packet discarding 119864

1=

depth difference between forwarding node and sending node1198642=difference of residual energy between current energy and

threshold energy and1198643= distance between forwarding node

and sending node

119875 (1198671) =

1

2

119875 (1198672) =

1

2

119875 (1198641| 1198671) =

119889119891minus 119889119904

119877if (119889119891minus 119889119904gt 0)

0 if (119889119891minus 119889119904le 0)

119875 (1198641| 1198672) =

1 minus

(119889119891minus 119889119904)

119877if (119889119891minus 119889119904ge 0)

minus (119889119891minus 119889119904)

119877if (119889119891minus 119889119904lt 0)

119875 (1198642| 1198671) =

119864119903minus 119864

th119903

119864max119903

minus 119864th119903

if (119864119903minus 119864

th119903gt 0)

0 if (119864119903minus 119864

th119903le 0)

119875 (1198642| 1198672) =

1 minus119864119903minus 119864

th119903

119864max119903

minus 119864th119903

if (119864119903minus 119864

th119903ge 0)

minus (119864119903minus 119864

th119903)

119864max119903

minus 119864th119903

if (119864119903minus 119864

th119903lt 0)

119875 (1198643| 1198671) =

119863

119877if (119863 gt 0)

0 if (119863 le 0)

1 minus119863

119877if (119863 ge 0)

(1)

Now we can calculate the probability of a nodersquos forwardingpacket and discarding packet by using the following condi-tional Bayesrsquo theorem

119875 (1198671| 119864111986421198643)

=119875 (1198641| 1198671) times 119875 (119864

2| 1198671) times 119875 (119864

3| 1198671) times 119875 (119867

1)

sum2

119896=1119875 (119867119896| 1198641) times 119875 (119867

119896| 1198642) times 119875 (119867

119896| 1198643) times 119875 (119867

119896)

119875 (1198672| 119864111986421198643)

=119875 (1198641| 1198672) times 119875 (119864

2| 1198672) times 119875 (119864

3| 1198672) times 119875 (119867

2)

sum2

119896=1119875 (119867119896| 1198641) times 119875 (119867

119896| 1198642) times 119875 (119867

119896| 1198643) times 119875 (119867

119896)

(2)

The forwarding node forwards the packet if 119875(1198671|119864111986421198643) gt

119875(1198672| 119864111986421198643) The forwarding node discards the packet if

119875(1198671| 119864111986421198643) lt 119875(119867

2| 119864111986421198643)

333 Reckoning the Link Expiration Time The link expi-ration time of any two nodes means the duration of theconnectivity of the two nodes within a fixed range 119877 Let 119899

1


and 1198992be two nodes within a fixed range 119877 These two nodes

move in 1205791 1206011and 1205792 1206012directions in the three-dimensional

space of underwater respectively Let their initial position be1199091015840

1 11991010158401 11991110158401and 119909

1015840

2 11991010158402 11991110158402 respectively after time 119905 and their

new coordinate will be 1199091 1199101 1199111and 119909

2 1199102 1199112 respectively

Suppose that they travel at the speed of 1199071ms and 119907

2ms

respectively and after time 119905 1198991passes 119889

1miter and 119899

2passes

1198892miter

1198891= 1199071119905

1198892= 1199072119905

(3)

New coordinates (with respect to old coordinates) can becalculated using the following formula

1199091= 1199091015840

1+ 1199091

= 1199091015840

1+ 1198891sin 1205791cos1206011

= 1199091015840

1+ 119905 (1199071sin 1205791cos1206011)

1199101= 1199101015840

1+ 1199101

= 1199101015840

1+ 1198891sin 1205791sin1206011

= 1199101015840

1+ 119905 (1199071sin 1205791sin1206011)

1199111= 1199111015840

1

= 1199111015840

1+ 1198891cos 1205791

= 1199111015840

1+ 119905 (1199071cos 1205791)

1199092= 1199091015840

2+ 1199092

= 1199091015840

2+ 1198892sin 1205792cos1206012

= 1199091015840

2+ 119905 (1199072sin 1205792cos1206012)

1199102= 1199101015840

2+ 1199102

= 1199101015840

2+ 1198892sin 1205792sin1206012

= 1199101015840

2+ 119905 (1199072sin 1205792sin1206012)

1199112= 1199111015840

2

= 1199111015840

2+ 1198892cos 1205792

= 1199111015840

2+ 119905 (1199072cos 1205792)

(4)

The distance between the two nodes at time 119905 can be found asfollows Let

119886 = (1199091015840

1minus 1199091015840

2)

119887 = (1199101015840

1minus 1199101015840

2)

119888 = (1199111015840

1minus 1199111015840

2)

119890 = (1199071sin 1205791cos1206011minus 1199072sin 1205792cos1206012)

119891 = (1199071sin 1205791sin1206011minus 1199072sin 1205792sin1206012)

119892 = (1199071cos 1205791minus 1199072cos 1205792)

(5)

Table 4 Routing table for the proposed UWSNs routing protocol

Node Forwarding probability LET1198731

FP(1198731) LET

1

1198732

FP(1198732) LET

2

1198733

FP(1198733) LET

3

1198734

FP(1198734) LET

4

119873119899

FP(119873119899) LET

119899

Now the distance between the two nodes after time 119905 can becalculated as follows

1198632= (119886 + 119890119905)

2+ (119887 + 119891119905)

2+ (119888 + 119892119905)

2

1199052(1198902+ 1198912+ 1198922) + 119905 (2119886119890 + 2119887119891 + 2119888119892) + 119886

2+ 1198872+ 1198882= 1198632

(6)

Now we assume that after time 119905 the distance between thesetwo nodes is 119877 which is the transmission range We cancalculate the time 119905 as follows

1199052(1198902+1198912+1198922) + 119905 (2119886119890+2119887119891+2119888119892)+119886

2+1198872+1198882= 1198772

1199052(1198902+1198912+1198922) + 119905 (2119886119890+2119887119891+2119888119892)+119886

2+1198872+1198882minus 1198772= 0

(7)

Again let

119898 = 1198902+ 1198912+ 1198922

119899 = 2119886119890 + 2119887119891 + 2119888119892

119900 = 1198862+ 1198872+ 1198882minus 1198772

(8)

Now it stands as follows

1198981199052+ 119899119905 + 119900 = 0

119905 =minus119899 plusmn radic1198992 minus 4119898119900

2119898

(9)

334 Routing Table Each node forms a routing table of threecolumns candidate forwarding nodes their correspondingprobability and link expiration time Routing table of theproposed routing protocol is demonstrated in Table 4 Let thesender node be 119878 and let its one-hop candidate forwardingnodes be (119873

1 1198732 119873

119899) within range 119877 and FP

119899and LET

represent the forwarding probability and the link expirationtime between the two nodes respectively

34 The Routing Algorithms of the Proposed Routing ProtocolIn this section we design an algorithm for our proposedrouting protocol For each phase a separate algorithm isimplemented here First the algorithm for the forwardingnode is illustrated in Algorithm 1 Second the algorithm forrouting table formation algorithm is given in Algorithm 2Third the packet forwarding algorithm for the sending nodeis shaped in Algorithm 3


Require RREQ messageEnsure RREP message(1) Extract RREQ message(2) Calculate Probability of packet forwarding

and discarding(3) if119875(119867

1| 119864111986421198643) gt 119875(119867

2| 119864111986421198643) then

(4) Send RREP message to the sending node(5) else(6) Discard the RREQ message(7) end if

Algorithm 1 Algorithm for forwarding nodes

4 Performance Evaluation

In this section we evaluate the performance of the proposedUWSNs routing protocol and compare the performance ofVBF [5]

41 Simulation Setting All simulations are performed usingthe network simulator (ns-2) [14] with an underwater sensornetwork simulation package (called Aqua-Sim) extensionWe performed simulations with a different number of sensornodes (ie 25 49 100 and 225) The position of eachnode is generated randomly Multiple sinks are randomlydeployed at the water surface Sink nodes are consideredas stationary while the sensor nodes are considered to bemobile at the speed of water current In order to measurethe performance of the proposed routing protocol differentspeeds ofwater current are considered and theminimumandthe maximum speeds of water current are taken as 1ms and10ms respectively In underwater environment the sensornodes move in random direction and for easy simulationwe have defined the direction of each sensor nodes in 3Dspace randomly We assume that control packets used in theprotocol are much shorter compared to data packets Wedefine the energy consumed for each data packet to be 1energy unit and for each hello packet to be 002 unit Thetransmission range of the simulation is fixed to 250m inall directions The threshold energy of the sensor nodes ispresumed to be 70 energy units For the ease of simulationthe source node is chosen from the bottom of the taken3D space The same broadcast media access control (MAC)protocol as in [5] is used in our simulations In this MACprotocol when a node has a packet to send it first senses thechannel If the channel is free it continues to broadcast thepacket Otherwise it backs off The packet will be dropped ifthe maximal number of back offs has been reached

42 Performance Metrics The following metrics are pointersused to appraise the performance of the proposed routingprotocol

(i) Network life time network life time expresses thetime that the energy of the first node in the networkturns to be fully exhausted

Required RREP messageEnsure Routing table(1) Broadcast RREQ message(2) Extract RREP message(3) Calculate LET (Link Expiration Time) for each

forwarding node(4) Form routing table

Algorithm 2 Routing table formation algorithm of sending node

1400

1200

1000

800

600

400

200

00 50 100 150 200 250

Number of nodes

Net

wor

klif

etim

e (s)

VBF

LETA

Figure 2 Comparison of network lifetime

(ii) Total energy consumption total energy consumptionis computed through the total energy consumed inpacket delivery including transmitting receiving andidling energy consumption of all nodes relaying thepacket from the source node to the sink node in thenetwork

(iii) Average end-to-end delay average end-to-end corre-sponds to the average time needed by a packet to gofrom the source node to any of the sinks

(iv) Packet deliver ratio packet delivery ratio is evaluatedas the ratio of the number of distinct packet capturedsuccessfully by the destination node to the totalnumber of packets spawned at the source node

43 Result and Analysis In this section the result and theanalysis of the simulation are discussed in detail

431 Network Life Time The network lifetime of LETA andVBF [5] in random topology is illustrated in Figure 2

It is observed that LETA offers improved performanceover VBF in the perspective of network life time LETAexceeds the network lifetime of VBF because VBF alwayschooses the nodes within a fixed vector and as a result asenor node may be selected again and again to forward data


Require Data packetEnsure Packet forwarding amp ACK(1) Initialize 119891 larr 119865119886119897119904119890 119886119888119896 larr 119865119886119897119904119890

(2)while 119894 le 119899amp119891 = 119865119886119897119904119890 do(3) 119873Target larr 119873

119894

(4) if119879LET ge (2119863119881) then(5) Forward packet(6) 119891 larr 119879119903119906119890

(7) 119894 larr 119894 + 1

(8) else(9) 119894 larr 119894 + 1

(10) end if(11) endwhile(12)Wait for (2119863119881)(13) if 119886119888119896 = 119865119886119897119904119890amp 119894 lt 119899 then(14) 119892119900119905119900 (2)

(15) else(16) Reform routing table(17) end if

Algorithm 3 Packet forwarding algorithm

Consequently the energy of such nodes is exhausted fast andthese nodesrsquo lifetime expires soon On the other hand LETAdoes not forward data to the sensor node in which residualenergy is less than the threshold energy and always selects thesensor node with higher residual energy It is a little chancefor a senor node to go down its energy below threshold anddies The control message hardly forces sensor nodesrsquo energyto be exhausted So the network lifetime increases as thenumber of sensor node increases in contrast in case of VBFif the number of sensor nodes increases the network lifetime will decrease since with increasing the number of sensornodes more sensor nodes attend to forward data and it isvery chanceful for a sensor node to die at any time BesidesVBF cannot avoid redundant packet transmissions Most ofthe time only one node in LETA forwards a data packet andthus saving energy and it leads to improve the life time of thebattery

432 Total Energy Consumption The comparison of theperformances of LETA and VBF [5] in terms of energyconsumption is illustrated in Figure 3

It is seen that the proposed protocol consumes less energythan that of the VBF protocol In LETA protocol only onenode takes part in forwarding packet The forwarding nodeowns the title of the fittest node As the sending node alwaysgives the node with highest probability priority to forwardpacket energy is much saved On the contrary in VBF morethan one node attends in forwarding the same packet as aresult higher energy is consumed in VBF protocol In LETAprotocol the control packet is implied to find out the fittestnode and to acknowledge the sender of its packet reachingto the forwarding node These control packets consume anegligible amount of energy as they are used locally andwhendata packet is available to send In VBF three types of controlpackets are used one is for fixing the destination and the

0 50 100 150 200 250Number of nodes

VBF

LETA

120

100

80

60

40

20

0

Ener

gyco

nsum

ptio

n (J

)

Figure 3 Comparison of total energy consumption of LETA withVBF

0 50 100 150 200 250Number of nodes

VBF

LETA

70

60

50

40

30

20

10

0

End-

to-e

nd d

elay

(s)

Figure 4 Comparison of average end-to-end delay of LETA withVBF

other two are for packet forwarding To fix up the destinationit has to flood the control packet which causes a lot of energyas the sender is deeper as it consumes more energy In VBFnode mobility is not guarded as a result with the increase ofnodes and node mobility much energy is being consumed

433 Average End-to-End Delay In Figure 4 end-to-enddelay of LETA and VBF [5] is shown respectively

LEAT always tries to send packet to the forwardingnode which is near to the surface as the probability offorwarding packet is calculated based on the depth and thedistance between the forwarding node and the sending nodeOn the contrary in VBF it takes much time to discover


100

90

80

70

60

50

40

30

20

10

Del

iver

yra

tio (

)

0 50 100 150 200 250Number of nodes

VBF

LETA

Figure 5 Comparison of packet delivery ratio of LETA with VBF

the destination node and for the response to come from thedestination node in VBF so the average end-to-end delay inVBF is larger than that of LETA As the velocity of watercurrent increases the end-to-end delay decreases as in bothprotocols In LETA there are a lot of forwarding nodeswhich are near to the surface to be chosen as target nodesBut in VBF to handle node mobility no direct techniqueis applied as a result less number of the forwarding nodesattend in forwarding packet with increasing node mobilityand it increases the end-to-end delay which is higher thanthat of LETA

434 Packet Delivery Ratio Figure 5 shows the delivery ratioas the function of the number of nodes

The delivery ratio of packet depends on how muchreliable and robust the protocol is The LETA is a reliableprotocol as it is using acknowledgment packet which con-firms a packetrsquos successful receiving by a forwarding nodeand it is robust because it floods control message locally Thepacket delivery ratio of LETA is higher than that of VBFAlthough in LETA in most of the cases only one node joinsin packet forwarding the packet delivery ratio is not belowthe expected level because the sender forwards the packet tothe fittest node and waits for the acknowledgment In VBFonly those nodes that are in the vector take part in forwardingpacket consequently with the increasing of node mobilitythe node can be out of the vector and this effect reduces thepacket delivery ratio in VBF

5 Conclusion

In this paper we introduce the link expiration time to handlenode mobility and probability to select a node as forwardingnode which is a novel technique Acknowledgment packetis used in this protocol to ensure error-free date packetrsquosreceiving by the forwarding node The protocol guarantees

the maximum level of network life time and end-to-enddelivery In the future we plan to adopt detour mechanism toavoid the void of zone and to develop better mobility handlemethod

Acknowledgment

Thisworkwas supported by theResearchCenter ofComputerScience and Engineering Mawlana Bhashani Science andTechnology University Tangail Bangladesh The authors aregrateful for this support

References

[1] I F Akyildiz D Pompili and T Melodia ldquoChallenges for effi-cient communication in underwater acoustic sensor networksrdquoACM Sigbed Review vol 1 no 2 pp 3ndash8 2004

[2] J Heidemann Y Li A Syed J Wills and W Ye ldquoUnderwatersensor networking research challenges and potential applica-tionsrdquo USCISI Technical Report ISI-TR-2005-603 2005

[3] J A Rice ldquoUndersea networked acoustic communication andnavigation for autonomous minecountermeasure systemsrdquo inProceedings of the 5th International Symposium on Technologyand the Mine Problem 2002

[4] L Guo P H Santschi M Baskaran and A Zindler ldquoDistribu-tion of dissolved and particulate in seawater from the gulf ofmexico and off cape hatteras as measured by simsrdquo Earth andPlanetary Science Letters vol 133 no 1-2 pp 117ndash128 1995

[5] P Xie J H Cui and L Lao ldquoVBF vector-based forwardingprotocol for underwater sensor networksrdquo in Networking 2006Networking Technologies Services and Protocols Performance ofComputer and Communication Networks Mobile and WirelessCommunications Systems vol 3976 pp 1216ndash1221 2006

[6] NNicolaou A See P Xie J H Cui andDMaggiorini ldquoImpro-ving the robustness of location-based routing for underwatersensor networksrdquo in Proceedings of the OCEANS Europe pp 1ndash6 June 2007

[7] N ChirdchooW S Soh and K C Chua ldquoSector-based routingwith destination location prediction for underwatermobilenetworksrdquo in Proceedings of the International Conference onAdvanced Information Networking and Applications Workshops(WAINA rsquo09) pp 1148ndash1153 IEEEComputer SocietyMay 2009

[8] M C Domingo and R Prior ldquoDesign and analysis of a GPS-free routing protocol for underwater wireless sensor networksin deep waterrdquo in Proceedings of the International Conference onSensor Technologies and Applications (SENSORCOMM rsquo07) pp215ndash220 IEEE October 2007

[9] Z Zhou and J H Cui ldquoEnergy efficient multi-path communi-cation for time-critical applications in underwater sensor net-worksrdquo in Proceedings of the 9th ACM International Symposiumon Mobile Ad Hoc Networking and Computing (MobiHoc rsquo08)pp 221ndash230 May 2008

[10] M Ayaz and A Abdullah ldquoHop-by-hop dynamic addressingbased (H2-DAB) routing protocol for underwater wirelesssensor networksrdquo in Proceedings of the International Conferenceon Information and Multimedia Technology (ICIMT rsquo09) pp436ndash441 Jeju Island Korea December 2009

[11] H Yan Z Shi and J H Cui ldquoDbr depth-based routing forunderwater sensor networksrdquo in NETWORKING 2008 Ad Hocand Sensor Networks Wireless Networks Next Generation Inter-net vol 4982 of Lecture Notes in Computer Science pp 72ndash86


[12] W K G Seah and H X Tan ldquoMultipath virtual sink archi-tecture for underwater sensor networksrdquo in Proceedings of theOCEANS 2006 Asia Pacific Conference May 2007

[13] M Ayaz A Abdullah I Faye and Y Batira ldquoAn efficient Dyna-mic Addressing based routing protocol for Underwater Wire-less Sensor Networksrdquo Computer Communications vol 35 no4 pp 475ndash486 2012

[14] TheNetwork Simulator NS-2 2002 httpwwwisiedunsnamnsdocindexhtml

International Journal of

AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

RoboticsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014


Active and Passive Electronic Components

Control Scienceand Engineering

Journal of



RotatingMachinery


Hindawi Publishing Corporation httpwwwhindawicom

Journal ofEngineeringVolume 2014

Submit your manuscripts athttpwwwhindawicom

VLSI Design



Shock and Vibration


Civil EngineeringAdvances in

Acoustics and VibrationAdvances in



Electrical and Computer Engineering

Journal of

Advances inOptoElectronics


Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

SensorsJournal of


Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014


Chemical EngineeringInternational Journal of Antennas and

Propagation




Navigation and Observation



DistributedSensor Networks



routing algorithm becomes a significant mission Althoughunderwater acoustic network has continued to be studied fordecades underwater networking and routing protocols arestill at the infant stage of research We have studied somerouting protocols to shape our own routing protocol

Vector-based forwarding (VBF) [5] guides the packetfrom the source to the destination Packets are forwarded onlyby those sensor nodes that arewithin the range119877of the vectorThe forwarding process of VBF is thought to be a routingpipe (virtual pipe) between the source and the destinationnodes The energy of the network is saved because only thenodes that come across the forwarding path are involvedin packet routing It provides small data delivery ratio insparse networks Moreover delivery ratio decreases whennodes are mobile and is sensitive to the routing pipersquos radiusHigh communication time in dense network is needed andmultiple nodes act as relay nodes

To reduce the high communication time and to handlenode mobility VBF routing protocol has been modified andproposed a hop-by-hop VBF (HH-VBF) [6] routing protocolThis protocol forms the routing pipe in a hop-by-hop fashionenhancing the packet delivery ratio significantly It does notuse a single virtual pipe and each node forwards packetbased on its current location When a node receives a packetit first holds the packet for sometime Each node in theneighborhood may hear the same packet multiple timesEach nodersquos overhearing the duplicate packet transmissionto control the forwarding of this packet is allowed in HH-VBF routing protocol In sparse networks HH-VBF candiscover a data delivery path as long as there exists one in thenetwork It also suffers from some disadvantages such as longpropagation delay high energy cost in dense networks andbeing not efficient enough with node mobility

In sector-based routing with destination location predic-tion [7] a node knows its own location and predicts thelocation of the destination node where the precise knowledgeof the destinationrsquos location is relaxed by it The senderdetermines its next hop using information received fromthe candidate nodes It eliminates the problem of havingmultiple nodes acting as relay nodes It does not require torebroadcast the request to send (RTS) every time it cannotfind a candidate node within its transmitting range In SBR-DLP node speed causes disconnections and it gives relativelylow PDR in sparse networks and has relatively high energyconsumption in dense networks where it performs best butbetter packet delivery ratio when all nodes are mobile

Distributed underwater clustering scheme (DUCS) [8]is an adaptive self-organizing protocol that forms clustersIt is considered that there are always data to be sent tothe sink by the underwater sensor nodes and that powercontrol can be used to adjust its transmission power Ittries to be adapted to the intrinsic properties of underwaterenvironments and uses a continually adjusted timing advancecombined with guard time values to minimize data loss andmaintain communication quality Nodes are organized intolocal clusters One node is selected as a cluster head foreach cluster All data coming from noncluster head nodes aretransmitted to their cluster head via a single hop Data arereceived by the cluster-head node and transmitted to the sink

(via the relays of other cluster heads) using multihop routingDUCS incorporates randomized rotation of the cluster headamong the sensors to avoid draining the battery of anyunderwater sensor in the network As the number of thenodes decrease in the network a slight decrease occurs in thenumber of data messages packet delivery ratio

Multipath routing [9] is energy-efficient networks andovercomes long propagation delay and adverse link condi-tions Depending on how the routes are selected there is astrong likelihood of contention occurring among nodes thatare on different routes but close to one another The localsink connections are assumed to be via high-speed linksbeing wired to a buoy on the surface equipped with RFcommunications link or an undersea high-speed optical fiberThe ultimate goal of the underwater network is to ensure thatdata are delivered to one or more of these local sinks whichcollectively form a virtual sink Connection is establishedthrough wire or optical fiber Backup routes are created bydeploying redundant nodes Contention occurs among nodesdue to redundancy

In H2-DAB [10] sink node broadcasts a hello packet andthe sensor node that receives the packet is assigned a HopID by incrementing the Hop ID existing in the hello packetof sink node The packet-receiving node broadcasts the hellopacket after updating the Hop ID of the received hello packetIn this way sensor nodes are given a unique address from sinknodes to source node When the packet is forwarded to thesink node it searches for the sensor nodes with the smallestHop ID To forward a packet this protocol utilizes only thehop count which is not a good indicator to forward packetbecause UWSN is an energy-constrained network It does notguarantee the network living time because the same node canbe chosen again and again to transfer a packet Moreover inthis protocol inquiry request and inquiry reply packets are tobe exploited at the time of the forwarding of the data packetswhich is costly in terms of delay and energy

Depth-based routing (DBR) protocol [11] is an underwa-ter sensor network routing protocol which is based on thedepth information of each sensor In this routing protocolno complete dimensional information of the location of thesensor nodes is required and it can manage a dynamic net-work InDBR to deliver a packet it determines that the closerto the destination the smaller the depth of the forwardingnodes and to receive a packet it compares between the depthretrieving of the previous hop and its receiving nodersquos depthfor the qualified candidates to forward the packet DBR hasgood energy efficiency but not somuch good performance forthe dense network where it has significant end-to-end delayand high total energy consumption

All of these discussed routing protocols for UWSNs areefficient and effective in their own ways In this paper wehave developed a routing protocol to overcome the disad-vantages of the vector-based routing protocol [11] In DBRthe forwarding node takes the decision of packet forwardingbased on only the depth which can make more forwardingnodes compatible to forward a packet because of the nodersquossame depth We introduce a novel technique by consideringBayesrsquo theorem to assess the target node In our forwardingtechnique we use depth residual energy and the distance










Water surface

Radio signals

Acoustic signals

Sink node

Sensor node




















1=



and sending node

119875 (1198671) =

1

2

119875 (1198672) =

1

2

119875 (1198641| 1198671) =

119889119891minus 119889119904

119877if (119889119891minus 119889119904gt 0)

0 if (119889119891minus 119889119904le 0)

119875 (1198641| 1198672) =

1 minus

(119889119891minus 119889119904)

119877if (119889119891minus 119889119904ge 0)

minus (119889119891minus 119889119904)

119877if (119889119891minus 119889119904lt 0)

119875 (1198642| 1198671) =

119864119903minus 119864

th119903

119864max119903

minus 119864th119903

if (119864119903minus 119864

th119903gt 0)

0 if (119864119903minus 119864

th119903le 0)

119875 (1198642| 1198672) =

1 minus119864119903minus 119864

th119903

119864max119903

minus 119864th119903

if (119864119903minus 119864

th119903ge 0)

minus (119864119903minus 119864

th119903)

119864max119903

minus 119864th119903

if (119864119903minus 119864

th119903lt 0)

119875 (1198643| 1198671) =

119863

119877if (119863 gt 0)

0 if (119863 le 0)

1 minus119863

119877if (119863 ge 0)

(1)


119875 (1198671| 119864111986421198643)

=119875 (1198641| 1198671) times 119875 (119864

2| 1198671) times 119875 (119864

3| 1198671) times 119875 (119867

1)

sum2

119896=1119875 (119867119896| 1198641) times 119875 (119867

119896| 1198642) times 119875 (119867

119896| 1198643) times 119875 (119867

119896)

119875 (1198672| 119864111986421198643)

=119875 (1198641| 1198672) times 119875 (119864

2| 1198672) times 119875 (119864

3| 1198672) times 119875 (119867

2)

sum2

119896=1119875 (119867119896| 1198641) times 119875 (119867

119896| 1198642) times 119875 (119867

119896| 1198643) times 119875 (119867

119896)

(2)



119875(1198671| 119864111986421198643) lt 119875(119867

2| 119864111986421198643)


1





1 11991010158401 11991110158401and 119909

1015840





2ms


1miter and 119899

2passes

1198892miter

1198891= 1199071119905

1198892= 1199072119905

(3)


1199091= 1199091015840

1+ 1199091

= 1199091015840

1+ 1198891sin 1205791cos1206011

= 1199091015840

1+ 119905 (1199071sin 1205791cos1206011)

1199101= 1199101015840

1+ 1199101

= 1199101015840

1+ 1198891sin 1205791sin1206011

= 1199101015840

1+ 119905 (1199071sin 1205791sin1206011)

1199111= 1199111015840

1

= 1199111015840

1+ 1198891cos 1205791

= 1199111015840

1+ 119905 (1199071cos 1205791)

1199092= 1199091015840

2+ 1199092

= 1199091015840

2+ 1198892sin 1205792cos1206012

= 1199091015840

2+ 119905 (1199072sin 1205792cos1206012)

1199102= 1199101015840

2+ 1199102

= 1199101015840

2+ 1198892sin 1205792sin1206012

= 1199101015840

2+ 119905 (1199072sin 1205792sin1206012)

1199112= 1199111015840

2

= 1199111015840

2+ 1198892cos 1205792

= 1199111015840

2+ 119905 (1199072cos 1205792)

(4)


119886 = (1199091015840

1minus 1199091015840

2)

119887 = (1199101015840

1minus 1199101015840

2)

119888 = (1199111015840

1minus 1199111015840

2)



119892 = (1199071cos 1205791minus 1199072cos 1205792)

(5)



FP(1198731) LET

1

1198732

FP(1198732) LET

2

1198733

FP(1198733) LET

3

1198734

FP(1198734) LET

4

119873119899

FP(119873119899) LET

119899


1198632= (119886 + 119890119905)

2+ (119887 + 119891119905)

2+ (119888 + 119892119905)

2

1199052(1198902+ 1198912+ 1198922) + 119905 (2119886119890 + 2119887119891 + 2119888119892) + 119886

2+ 1198872+ 1198882= 1198632

(6)


1199052(1198902+1198912+1198922) + 119905 (2119886119890+2119887119891+2119888119892)+119886

2+1198872+1198882= 1198772

1199052(1198902+1198912+1198922) + 119905 (2119886119890+2119887119891+2119888119892)+119886

2+1198872+1198882minus 1198772= 0

(7)

Again let

119898 = 1198902+ 1198912+ 1198922

119899 = 2119886119890 + 2119887119891 + 2119888119892

119900 = 1198862+ 1198872+ 1198882minus 1198772

(8)


1198981199052+ 119899119905 + 119900 = 0


2119898

(9)


1 1198732 119873


119899and LET






1| 119864111986421198643) gt 119875(119867

2| 119864111986421198643) then











1400

1200

1000

800

600

400

200

00 50 100 150 200 250

Number of nodes

Net

wor

klif

etim

e (s)

VBF

LETA











119894


(7) 119894 larr 119894 + 1

(8) else(9) 119894 larr 119894 + 1







0 50 100 150 200 250Number of nodes

VBF

LETA

120

100

80

60

40

20

0

Ener

gyco

nsum

ptio

n (J

)


0 50 100 150 200 250Number of nodes

VBF

LETA

70

60

50

40

30

20

10

0

End-

to-e

nd d

elay

(s)






100

90

80

70

60

50

40

30

20

10

Del

iver

yra

tio (

)

0 50 100 150 200 250Number of nodes

VBF

LETA





5 Conclusion



Acknowledgment


References


















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation


















Water surface

Radio signals

Acoustic signals

Sink node

Sensor node




















1=



and sending node

119875 (1198671) =

1

2

119875 (1198672) =

1

2

119875 (1198641| 1198671) =

119889119891minus 119889119904

119877if (119889119891minus 119889119904gt 0)

0 if (119889119891minus 119889119904le 0)

119875 (1198641| 1198672) =

1 minus

(119889119891minus 119889119904)

119877if (119889119891minus 119889119904ge 0)

minus (119889119891minus 119889119904)

119877if (119889119891minus 119889119904lt 0)

119875 (1198642| 1198671) =

119864119903minus 119864

th119903

119864max119903

minus 119864th119903

if (119864119903minus 119864

th119903gt 0)

0 if (119864119903minus 119864

th119903le 0)

119875 (1198642| 1198672) =

1 minus119864119903minus 119864

th119903

119864max119903

minus 119864th119903

if (119864119903minus 119864

th119903ge 0)

minus (119864119903minus 119864

th119903)

119864max119903

minus 119864th119903

if (119864119903minus 119864

th119903lt 0)

119875 (1198643| 1198671) =

119863

119877if (119863 gt 0)

0 if (119863 le 0)

1 minus119863

119877if (119863 ge 0)

(1)


119875 (1198671| 119864111986421198643)

=119875 (1198641| 1198671) times 119875 (119864

2| 1198671) times 119875 (119864

3| 1198671) times 119875 (119867

1)

sum2

119896=1119875 (119867119896| 1198641) times 119875 (119867

119896| 1198642) times 119875 (119867

119896| 1198643) times 119875 (119867

119896)

119875 (1198672| 119864111986421198643)

=119875 (1198641| 1198672) times 119875 (119864

2| 1198672) times 119875 (119864

3| 1198672) times 119875 (119867

2)

sum2

119896=1119875 (119867119896| 1198641) times 119875 (119867

119896| 1198642) times 119875 (119867

119896| 1198643) times 119875 (119867

119896)

(2)



119875(1198671| 119864111986421198643) lt 119875(119867

2| 119864111986421198643)


1





1 11991010158401 11991110158401and 119909

1015840





2ms


1miter and 119899

2passes

1198892miter

1198891= 1199071119905

1198892= 1199072119905

(3)


1199091= 1199091015840

1+ 1199091

= 1199091015840

1+ 1198891sin 1205791cos1206011

= 1199091015840

1+ 119905 (1199071sin 1205791cos1206011)

1199101= 1199101015840

1+ 1199101

= 1199101015840

1+ 1198891sin 1205791sin1206011

= 1199101015840

1+ 119905 (1199071sin 1205791sin1206011)

1199111= 1199111015840

1

= 1199111015840

1+ 1198891cos 1205791

= 1199111015840

1+ 119905 (1199071cos 1205791)

1199092= 1199091015840

2+ 1199092

= 1199091015840

2+ 1198892sin 1205792cos1206012

= 1199091015840

2+ 119905 (1199072sin 1205792cos1206012)

1199102= 1199101015840

2+ 1199102

= 1199101015840

2+ 1198892sin 1205792sin1206012

= 1199101015840

2+ 119905 (1199072sin 1205792sin1206012)

1199112= 1199111015840

2

= 1199111015840

2+ 1198892cos 1205792

= 1199111015840

2+ 119905 (1199072cos 1205792)

(4)


119886 = (1199091015840

1minus 1199091015840

2)

119887 = (1199101015840

1minus 1199101015840

2)

119888 = (1199111015840

1minus 1199111015840

2)



119892 = (1199071cos 1205791minus 1199072cos 1205792)

(5)



FP(1198731) LET

1

1198732

FP(1198732) LET

2

1198733

FP(1198733) LET

3

1198734

FP(1198734) LET

4

119873119899

FP(119873119899) LET

119899


1198632= (119886 + 119890119905)

2+ (119887 + 119891119905)

2+ (119888 + 119892119905)

2

1199052(1198902+ 1198912+ 1198922) + 119905 (2119886119890 + 2119887119891 + 2119888119892) + 119886

2+ 1198872+ 1198882= 1198632

(6)


1199052(1198902+1198912+1198922) + 119905 (2119886119890+2119887119891+2119888119892)+119886

2+1198872+1198882= 1198772

1199052(1198902+1198912+1198922) + 119905 (2119886119890+2119887119891+2119888119892)+119886

2+1198872+1198882minus 1198772= 0

(7)

Again let

119898 = 1198902+ 1198912+ 1198922

119899 = 2119886119890 + 2119887119891 + 2119888119892

119900 = 1198862+ 1198872+ 1198882minus 1198772

(8)


1198981199052+ 119899119905 + 119900 = 0


2119898

(9)


1 1198732 119873


119899and LET






1| 119864111986421198643) gt 119875(119867

2| 119864111986421198643) then











1400

1200

1000

800

600

400

200

00 50 100 150 200 250

Number of nodes

Net

wor

klif

etim

e (s)

VBF

LETA











119894


(7) 119894 larr 119894 + 1

(8) else(9) 119894 larr 119894 + 1







0 50 100 150 200 250Number of nodes

VBF

LETA

120

100

80

60

40

20

0

Ener

gyco

nsum

ptio

n (J

)


0 50 100 150 200 250Number of nodes

VBF

LETA

70

60

50

40

30

20

10

0

End-

to-e

nd d

elay

(s)






100

90

80

70

60

50

40

30

20

10

Del

iver

yra

tio (

)

0 50 100 150 200 250Number of nodes

VBF

LETA





5 Conclusion



Acknowledgment


References


















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation
























1=



and sending node

119875 (1198671) =

1

2

119875 (1198672) =

1

2

119875 (1198641| 1198671) =

119889119891minus 119889119904

119877if (119889119891minus 119889119904gt 0)

0 if (119889119891minus 119889119904le 0)

119875 (1198641| 1198672) =

1 minus

(119889119891minus 119889119904)

119877if (119889119891minus 119889119904ge 0)

minus (119889119891minus 119889119904)

119877if (119889119891minus 119889119904lt 0)

119875 (1198642| 1198671) =

119864119903minus 119864

th119903

119864max119903

minus 119864th119903

if (119864119903minus 119864

th119903gt 0)

0 if (119864119903minus 119864

th119903le 0)

119875 (1198642| 1198672) =

1 minus119864119903minus 119864

th119903

119864max119903

minus 119864th119903

if (119864119903minus 119864

th119903ge 0)

minus (119864119903minus 119864

th119903)

119864max119903

minus 119864th119903

if (119864119903minus 119864

th119903lt 0)

119875 (1198643| 1198671) =

119863

119877if (119863 gt 0)

0 if (119863 le 0)

1 minus119863

119877if (119863 ge 0)

(1)


119875 (1198671| 119864111986421198643)

=119875 (1198641| 1198671) times 119875 (119864

2| 1198671) times 119875 (119864

3| 1198671) times 119875 (119867

1)

sum2

119896=1119875 (119867119896| 1198641) times 119875 (119867

119896| 1198642) times 119875 (119867

119896| 1198643) times 119875 (119867

119896)

119875 (1198672| 119864111986421198643)

=119875 (1198641| 1198672) times 119875 (119864

2| 1198672) times 119875 (119864

3| 1198672) times 119875 (119867

2)

sum2

119896=1119875 (119867119896| 1198641) times 119875 (119867

119896| 1198642) times 119875 (119867

119896| 1198643) times 119875 (119867

119896)

(2)



119875(1198671| 119864111986421198643) lt 119875(119867

2| 119864111986421198643)


1





1 11991010158401 11991110158401and 119909

1015840





2ms


1miter and 119899

2passes

1198892miter

1198891= 1199071119905

1198892= 1199072119905

(3)


1199091= 1199091015840

1+ 1199091

= 1199091015840

1+ 1198891sin 1205791cos1206011

= 1199091015840

1+ 119905 (1199071sin 1205791cos1206011)

1199101= 1199101015840

1+ 1199101

= 1199101015840

1+ 1198891sin 1205791sin1206011

= 1199101015840

1+ 119905 (1199071sin 1205791sin1206011)

1199111= 1199111015840

1

= 1199111015840

1+ 1198891cos 1205791

= 1199111015840

1+ 119905 (1199071cos 1205791)

1199092= 1199091015840

2+ 1199092

= 1199091015840

2+ 1198892sin 1205792cos1206012

= 1199091015840

2+ 119905 (1199072sin 1205792cos1206012)

1199102= 1199101015840

2+ 1199102

= 1199101015840

2+ 1198892sin 1205792sin1206012

= 1199101015840

2+ 119905 (1199072sin 1205792sin1206012)

1199112= 1199111015840

2

= 1199111015840

2+ 1198892cos 1205792

= 1199111015840

2+ 119905 (1199072cos 1205792)

(4)


119886 = (1199091015840

1minus 1199091015840

2)

119887 = (1199101015840

1minus 1199101015840

2)

119888 = (1199111015840

1minus 1199111015840

2)



119892 = (1199071cos 1205791minus 1199072cos 1205792)

(5)



FP(1198731) LET

1

1198732

FP(1198732) LET

2

1198733

FP(1198733) LET

3

1198734

FP(1198734) LET

4

119873119899

FP(119873119899) LET

119899


1198632= (119886 + 119890119905)

2+ (119887 + 119891119905)

2+ (119888 + 119892119905)

2

1199052(1198902+ 1198912+ 1198922) + 119905 (2119886119890 + 2119887119891 + 2119888119892) + 119886

2+ 1198872+ 1198882= 1198632

(6)


1199052(1198902+1198912+1198922) + 119905 (2119886119890+2119887119891+2119888119892)+119886

2+1198872+1198882= 1198772

1199052(1198902+1198912+1198922) + 119905 (2119886119890+2119887119891+2119888119892)+119886

2+1198872+1198882minus 1198772= 0

(7)

Again let

119898 = 1198902+ 1198912+ 1198922

119899 = 2119886119890 + 2119887119891 + 2119888119892

119900 = 1198862+ 1198872+ 1198882minus 1198772

(8)


1198981199052+ 119899119905 + 119900 = 0


2119898

(9)


1 1198732 119873


119899and LET






1| 119864111986421198643) gt 119875(119867

2| 119864111986421198643) then











1400

1200

1000

800

600

400

200

00 50 100 150 200 250

Number of nodes

Net

wor

klif

etim

e (s)

VBF

LETA











119894


(7) 119894 larr 119894 + 1

(8) else(9) 119894 larr 119894 + 1







0 50 100 150 200 250Number of nodes

VBF

LETA

120

100

80

60

40

20

0

Ener

gyco

nsum

ptio

n (J

)


0 50 100 150 200 250Number of nodes

VBF

LETA

70

60

50

40

30

20

10

0

End-

to-e

nd d

elay

(s)






100

90

80

70

60

50

40

30

20

10

Del

iver

yra

tio (

)

0 50 100 150 200 250Number of nodes

VBF

LETA





5 Conclusion



Acknowledgment


References


















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation













1 11991010158401 11991110158401and 119909

1015840





2ms


1miter and 119899

2passes

1198892miter

1198891= 1199071119905

1198892= 1199072119905

(3)


1199091= 1199091015840

1+ 1199091

= 1199091015840

1+ 1198891sin 1205791cos1206011

= 1199091015840

1+ 119905 (1199071sin 1205791cos1206011)

1199101= 1199101015840

1+ 1199101

= 1199101015840

1+ 1198891sin 1205791sin1206011

= 1199101015840

1+ 119905 (1199071sin 1205791sin1206011)

1199111= 1199111015840

1

= 1199111015840

1+ 1198891cos 1205791

= 1199111015840

1+ 119905 (1199071cos 1205791)

1199092= 1199091015840

2+ 1199092

= 1199091015840

2+ 1198892sin 1205792cos1206012

= 1199091015840

2+ 119905 (1199072sin 1205792cos1206012)

1199102= 1199101015840

2+ 1199102

= 1199101015840

2+ 1198892sin 1205792sin1206012

= 1199101015840

2+ 119905 (1199072sin 1205792sin1206012)

1199112= 1199111015840

2

= 1199111015840

2+ 1198892cos 1205792

= 1199111015840

2+ 119905 (1199072cos 1205792)

(4)


119886 = (1199091015840

1minus 1199091015840

2)

119887 = (1199101015840

1minus 1199101015840

2)

119888 = (1199111015840

1minus 1199111015840

2)



119892 = (1199071cos 1205791minus 1199072cos 1205792)

(5)



FP(1198731) LET

1

1198732

FP(1198732) LET

2

1198733

FP(1198733) LET

3

1198734

FP(1198734) LET

4

119873119899

FP(119873119899) LET

119899


1198632= (119886 + 119890119905)

2+ (119887 + 119891119905)

2+ (119888 + 119892119905)

2

1199052(1198902+ 1198912+ 1198922) + 119905 (2119886119890 + 2119887119891 + 2119888119892) + 119886

2+ 1198872+ 1198882= 1198632

(6)


1199052(1198902+1198912+1198922) + 119905 (2119886119890+2119887119891+2119888119892)+119886

2+1198872+1198882= 1198772

1199052(1198902+1198912+1198922) + 119905 (2119886119890+2119887119891+2119888119892)+119886

2+1198872+1198882minus 1198772= 0

(7)

Again let

119898 = 1198902+ 1198912+ 1198922

119899 = 2119886119890 + 2119887119891 + 2119888119892

119900 = 1198862+ 1198872+ 1198882minus 1198772

(8)


1198981199052+ 119899119905 + 119900 = 0


2119898

(9)


1 1198732 119873


119899and LET






1| 119864111986421198643) gt 119875(119867

2| 119864111986421198643) then











1400

1200

1000

800

600

400

200

00 50 100 150 200 250

Number of nodes

Net

wor

klif

etim

e (s)

VBF

LETA











119894


(7) 119894 larr 119894 + 1

(8) else(9) 119894 larr 119894 + 1







0 50 100 150 200 250Number of nodes

VBF

LETA

120

100

80

60

40

20

0

Ener

gyco

nsum

ptio

n (J

)


0 50 100 150 200 250Number of nodes

VBF

LETA

70

60

50

40

30

20

10

0

End-

to-e

nd d

elay

(s)






100

90

80

70

60

50

40

30

20

10

Del

iver

yra

tio (

)

0 50 100 150 200 250Number of nodes

VBF

LETA





5 Conclusion



Acknowledgment


References


















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation












1| 119864111986421198643) gt 119875(119867

2| 119864111986421198643) then











1400

1200

1000

800

600

400

200

00 50 100 150 200 250

Number of nodes

Net

wor

klif

etim

e (s)

VBF

LETA











119894


(7) 119894 larr 119894 + 1

(8) else(9) 119894 larr 119894 + 1







0 50 100 150 200 250Number of nodes

VBF

LETA

120

100

80

60

40

20

0

Ener

gyco

nsum

ptio

n (J

)


0 50 100 150 200 250Number of nodes

VBF

LETA

70

60

50

40

30

20

10

0

End-

to-e

nd d

elay

(s)






100

90

80

70

60

50

40

30

20

10

Del

iver

yra

tio (

)

0 50 100 150 200 250Number of nodes

VBF

LETA





5 Conclusion



Acknowledgment


References


















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation












119894


(7) 119894 larr 119894 + 1

(8) else(9) 119894 larr 119894 + 1







0 50 100 150 200 250Number of nodes

VBF

LETA

120

100

80

60

40

20

0

Ener

gyco

nsum

ptio

n (J

)


0 50 100 150 200 250Number of nodes

VBF

LETA

70

60

50

40

30

20

10

0

End-

to-e

nd d

elay

(s)






100

90

80

70

60

50

40

30

20

10

Del

iver

yra

tio (

)

0 50 100 150 200 250Number of nodes

VBF

LETA





5 Conclusion



Acknowledgment


References


















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










100

90

80

70

60

50

40

30

20

10

Del

iver

yra

tio (

)

0 50 100 150 200 250Number of nodes

VBF

LETA





5 Conclusion



Acknowledgment


References


















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation











RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation









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