Mddle-East Journal of Scentfc Research 2 (): 566-574, 202 ISSN 990-9233 IDOSI Publcatons, 202 DOI: 0.5829/dos.mejsr.202.2..43 Performance Improvement of Drect Dffuson Algorthm n Sensor Networks Akbar Bemana Islamc Azad Unversty, Dashtestan Branch, Borazjan, Iran Abstract: Provdng methods n wreless sensor networks to transmt data at desrable rate wth consderng crtera such as furnshng energy, storage and processng constrants s promnent. In ths paper a routng metrc s suggested for determnng the valdty of paths to select ntermedate node. Ths valdty s calculated accordng to the factors of lnk s relablty, remanng energy of nodes, buffer capacty and transmsson delay. The proposed metrc s appled on AODV and drected dffuson algorthms. Carryng out multple analyses and smulatons, we have shown the effcency of ths proposed routng metrc. The expermental results show that the delay and packet loss of the proposed method are less than the orgnal algorthm. Also the energy consumpton n proposed method s reduced. Key words: Sensor networks Drected dffuson AODV Routng QoS INTRODUCTION In IP-based and Ad-Hoc Networks many mechansms have been proposed to perform routng process whch A wreless sensor network conssts of a number of cannot drectly apply to wreless sensor networks sensor nodes spread across a geographcal area. Each because of ther nherently dstnct attrbutes. Global sensor node has a sensng capablty as well as lmted addressng n sensor nodes s utlzed. Also, a snk node energy supply, computaton power, memory and gathers data from other sensor nodes n network. communcaton ablty. These networks are ncreasngly Ths characterstc makes a dstnct dfference from above beng used for managng and controllng emergency mentoned networks. Furthermore, excessve traffc due to stuatons because of ther accurate and rapd deployment nodes movement, lnk breakage and etc. n sensor characterstcs. networks are problems whch affect routng protocols. Nodes n a sensor network have very lmted energy To optmze node energy consumpton and to cater supples whch are always equpped wth battery and t s the desred QoS n sensor networks several routng almost mpossble to recharge or replace the battery after algorthms have been proposed. deployment. Therefore, energy effcency s one key ssue An energy-aware QoS routng protocol ntroduced n wreless sensor networks. Also bandwdth, storage for sensor networks []. Cost and delay are the and processng constrants cause to decrease bt rate. constrants whch are consdered to reduce Ths problem brngs about applcatons of wreless sensor communcaton error and node's energy consumpton. network face serous challenges. For example, enterng a SAR, Sequental Assgnment Routng, s a routng target nsde an area of nterest, the delay to report the algorthm whch ntroduces organzaton and moblty sensed event could be crtcal. If the reported event s not management n sensor networks [2]. receved by the snk node wthn the deadlne, the end-to- To extend the sensor network lfetme n [3], DERP, end (ETE) delay requrement s not satsfed. After Delay-Mnmum Energy-Aware Routng Protocol, has locatng and detectng the target, sensor nodes may been proposed. The am of DERP s to mnmze delay n perodcally report that event to a snk node. Reducng network consderng energy. Furthermore, to prolong the delay s an mportant goal n wreless sensor networks. network lfetme n a scheme based on Zgbee AODV has Consderng the above reasons, ntroducng methods been proposed regardng to communcaton delay [9]. to support energy savng and reducng delay are strongly Drected dffuson s a routng protocol whch s used requested. Choosng an effcent routng algorthm to n wreless sensor networks. The am of ths method s to transmt packets between nodes has a drect effect to fnd effcent routes between nodes consderng desred optmze energy and reduce packets delay of nodes. QoS. Each task s reflected as an nterest. To perform a Correspondng Author: Akbar Bemana, Islamc Azad Unversty, Dashtestan Branch, Borazjan, Iran. 566
task, an nterest process wll be spread n a related area. equaton, below a dstance D, nodes exhbt full An nterested node, a snk node, broadcasts nterest connectvty, PRR s equal to. Nodes are dsconnected messages nto the network durng a floodng process. f they are at least dstance D2 away from each other. In On the other hand, a node sends these nterest messages the transtonal regon between D and D2, the expected contanng detaled descrpton to advertse tself as a recepton rate decreases smoothly wth some varaton. snk canddate node. When ths nterest s receved by a node, the node stores sender specfcatons and assgns a gradent regardng sender of nterest message. d < D The assgned gradent shows drecton of data stream and PRR = + X D < d < D () D2 d 2 D2 D 0 d > D2 status of request whch can be actve, nactve, or updatng necessty. Recevng nterest messages from 0 several neghbors, gradents wll be assgned for each of them. If a node predcate route accordng to prevous b Where [.] a = max{a, mn{b,.}} and X 2 N (0, ) s a gradent or geographcal nformaton, request wll be sent Gaussan varable wth varance 2. only to correlated canddate neghbors otherwse, request For our analyses and smulatons we assume that wll be sent to all adjacent neghbors. Recevng an nodes are unformly dstrbuted over a 200 * 200 m feld a nterest message by a node, t actvates ts sensor to maxmum rado range of 30 m wth parameters D = 0, collect requested data and to send t [4]. D2 = 30 and = 0.3. Furthermore, the network s statonary Brefly the drected dffuson algorthm uses three wthout moblty. We consder two nodes to be neghbors steps n sensng data transmsson. The frst step s that f the packet recepton rate s at least %. the sensng task (nterest) s dssemnated throughout the sensor network as shown n Fg. (a). The second Metrcs: Routng metrc s a parameter that based on step s that the ntermedate nodes relayng nterests valdty of paths whch n the routng process selects create and save the nformaton of the prevous hop as optmzed paths. ther routng nformaton called gradents as shown n The wreless sensor network s presented by a graph Fg. (b). A gradent s utlzed as a routng state toward G=(V,E), where V s the set of nodes, each node the nformaton collectng (snk) node when sensng data representng a sensor and E V V s the set of graph s relayed. As the thrd step, the orgnators select and edges for lnks between any two nodes. To choose the renforce one or a small number of these paths that are approprate nodes for routng, every node s gven ts better for sensng data transfer as shown n Fg. (c). remanng energy and buffer free space and a packet The man drawbacks of ths protocol are related to falure recepton rate s assgned to every lnk. recovery, QoS provsonng and global energy balancng. Ths metrc consders the path energy effcency and Many works have been recently done to mprove the the delay experenced along ths path. We defne path effcency of ths protocol. So n ths paper we extend defcency, E, to be the rato of the path energy effcency, Drected Dffuson algorthm based on our proposed Eeff, to the delay requred to transmt a packet from source metrc, whch n the routng process selects optmzed to the destnaton. paths. By analyss and smulaton, we have shown the E eff effcency of ths proposed routng protocol. E = The paper s organzed as follows. Secton 2, delay (2) proposes the system model. Secton 3, provdes the detals of the metrc, applyng the metrc on AODV [7] At frst, we used two parameter n our proposed algorthm and applyng the metrc on drected dffuson Metrc, namely delvery rate and energy effcency. The algorthm along present smulaton method along wth delvery rate E r quantfes the fracton of packets that results s gven secton4, fnally secton 5 gves orgnate at a source node and are properly receved at the conclusons and descrbe future drectons. snk. Snce each forwardng node consumes a certan amount of energy for packet recepton and transmsson, System Model: In our analyses and smulatons, we use the energy effcency E eff quantfes the rato between the model defned n [5] and [6]. Ths model captures the delvery rate E rand consumed network energy E e. That s, packet recepton rate (PRR) between two nodes as the energy effcency of a sngle node regardng packet follows. The behavor s modeled by Eq. () n ths forwardng towards the snk can be calculated by. 567
E eff Er E = = r E t e e E ˆ = prr ( E + b ) + a ( b + E ) 2 e, + e e Er prr kk, +, k destnaton =, k destnaton kk, + (3) E = ( ( prr ) ) (9) Where t denotes the average number of packet By replacng E rand E en Eq. (3), the energy effcency transmssons requred reachng the snk and e s the s gven by: correspondng energy for each packet transmsson and the requred energy could then be calculated as: (0) E = ( a) e = e + n. e + (N - n). e (4) tx rx h r ( ( prrkk, + ) ), k destnaton eff ( prr, + ( Ee+ b) + ab)( a ) Where e tx and e rx are the amount of energy for packet ( ( prrkk, + ) ) transmsson and recevng, n s the number of addressed () E = ( a) recevers and N s the number of neghbors n delay( prr ( E + b) + ab)( a ) communcaton range. e h quantfes the amount of energy requred only for decodng the packet header. We assume, k destnaton, + e The remanng energy of the forwardng node named that nodes who are not recevers of a packet wll turn ther e. In each separate node there s a varable parameter for rados off as soon as they have heard the header. e. Calculaton of the related parameter for each node wll Accordng to the sensor board hardware, we set e rx = be done n one span of alternatve basc rate of ths 0.375 and e tx =. parameter equal to consumpton of capacty n the source At frst for E computaton, the requred energy for energy. By applyng the remanng energy n the routng e the packet delvery for the frst transmsson s: (5) metrc, the path effcency E s:, k destnaton, + e kk, + ( ( prr ) ) E = ( a) * e delay( prr ( E + b) + ab)( a ) Usng a recursve calculaton, the requred energy for th the packet delvery for the R transmsson s gven by: Furthermore, end to end delay and packet delvery ˆ Ee = prr, + ( Ee+ b) + ab (6) rato are drectly related to the work traffc load of the ntermedate nodes. As such, hgh traffc load of node Fnally, the requred energy for packet delvery s ncreases the delay and work traffc, whch lead to greater energy consumpton. In ths work, t s proposed that for ( prr, + ( Ee+ b) + ab)( a ) (7) traffc load balancng of nodes, the buffer space s Ee = a ncluded n the metrc. Fgure depcts the shape of makng a model of one node as a server and a buffer wth Where PRR, + s the packet recepton rate for the determned capacty. forwarder node, E e s ts energy cost that refers to the Valdty of each node s the rate of buffer empty energy consumpton from the source to the node +. b capacty to the buffer actual sze. Valdty n each node =e tx+e rx and a=- prr,+. has been calculated by tself. It s represented by: In the fnte retransmsson case, each node s allowed to use up to R retransmssons to successfully delver a free space of Queue Vl = (3) data packet to ts forwardng node. The number of all space of Queue allowed retransmsson s dependent to Mac layer. In the V L represents the packet servce rate of node valdty. sngle-lnk case wthout retransmssons, the end-to-end Therefore, f a node has hgh percentage of V L, t shows delvery rate from a source node to the snk s: the lower capacty of node so the node s desderatum for Where s the path from source to snk and prr k, k+ s the packet recepton rate between node k and ts forwarder k + That prr k,k+ computed from the eq. (). Allowng up to R retransmssons, the delver rate changes to: (8) Fnally the path effcency s calculated by: Fg. : Node buffer server (2) 568
selectng. In the other hand, f valdty s near to zero, the the nformaton collectng (snk) node when sensng data node buffer s full and ths node assgned as crass, s relayed. As the thrd step, the orgnators select and because wth false selecton t the node nformaton dropt renforce one or a small number of these paths that are s possble. So, we need to retransmt and ths operaton better for sensng data transfer. wastes more energy and reduces node s energy. The am of the proposed metrc s to forward packets For applyng parameter V L, we know f the buffer of from a node to adjacent neghbors and ths approach has one node s full (V L =0) and practcally ths node can't an outstandng operaton n the networks wth flat servce, so route effcency s zero (E=0) and f the buffer structure. In the other hand, the drected dffuson s completely empty (V L =) route effcency s related to protocol has neghbor-to-neghbor routng characterstc other route effcency parameters. Also f V L>0 then path and t s sutable for flatten network structure. The effcency (E) and E' s postve, therefore path effcency selected protocol s specalzed for sensor networks. s ncreased proportonal to V L, E f (v l ). Negotaton between neghborhood nodes s another In ths paper we consder f (v L) = V L. Smulaton ablty of the drected dffuson protocol and ths shows the effectveness of V L. The effect of ths parameter negotaton s effcent and well sutable to establsh ncreases n hgh traffc. Fnally, regardng the buffer routes. Furthermore, the proposed algorthm sets the man capacty of the node, V L, n the routng metrc must polcy based on the negotaton between neghbors. balance the network load. So the path effcency s Therefore, by the selecton of the drected dffuson calculated by protocol as a platform to smulate the proposed algorthm, prrkk, + * e requred condtons are feasble to make a negotaton., k destnaton E ( a) * V L delay( prr, + ( Ee+ b) + ab)( a ) (4) Also, the drected dffuson protocol utlzes a routng algorthm based on mnmum delay such as a shortest route. Thus, t s possble to compare the modfed Ths s our proposed metrc whch s capable of drected dffuson algorthm wth the orgnal the drected ncludng delay, energy, lnk relablty, as well as capacty dffuson protocol. buffer factors. In the drected dffuson protocol always shortest We apply proposed Metrc at frst on AODV path between the source and destnaton nodes s algorthm and then on drect dffuson (DD) algorthm that selected to transmt traffc and t s cause to consume the s especally wreless sensor network and then nvestgate energy of ntermedate nodes quckly. Specally, n large the effcency of ths proposed routng metrc. scaled networks and n case of hgh data transmsson n a specfed zone of a network ths problem s so severe. Drected Dffuson: Drected dffuson s a data-centrc Another drawback whch tolerates ths problem s routng protocol. In a Wreless Sensor network the data occurred durng the evacuaton of a route. In ths tme the that the network can provde s nterestng, not mostly next shortest route, the adjacent routes of the specfc nodes. In order to receve data, an nterested current route, wll be selected and ths phenomena cause node (a snk ) floods the network wth an nterest to segregate the network durng the tme. Therefore, we message. Ths message contans a detaled descrpton of need a more far soluton to dstrbute the transmtted the event t s nterested n. When ths nterest s receved traffc of a source node to a destnaton node through by a node, t sets up a gradent to the neghbor from ntermedate nodes. whch t heard the nterest. If t hears the same nterest After proposng effectve reasons on selectng the from several neghbors, gradents wll be set up for each drected dffuson protocol n the rest of ths secton, the one of them. Ths focus on neghbors s a specfc feature effect s of exsted operatve on the polcy of the proposed of drected dffuson, whch allows the protocol to scale drected dffuson algorthm wll be explaned. wth the number of nodes n the network. Brefly the drected dffuson algorthm uses three AODV Routng Protocol: AODV routng protocol s a steps n sensng data transmsson. The frst step s that reactve routng algorthm. It mantans the establshed the sensng task (nterest) s dssemnated throughout the routes as long as they are needed by the sources. AODV sensor network. The second step s that the ntermedate uses sequence numbers to ensure the freshness of routes. nodes relayng nterests create and save the nformaton Route Dscovery The route dscovery process s ntated of the prevous hop as ther routng nformaton called whenever a traffc source needs a route to a destnaton. gradents. A gradent s utlzed as a routng state toward Route dscovery typcally nvolves a network-wde flood 569
Fg. 2: Route request message format Felds Destnaton Sequence number Next Hop Hop Count Max effcency Descrpton Destnaton Address Sequence number of the prevous Number message Next node address Hop Count to destnaton Valdty of the route Table : Routng table Hop Sequence Max Src ID Count Number PRR effcency Destnaton ID of route request (RREQ) packets targetng the destnaton and watng for a route reply (RREP). Ths algorthm mantans these routes as long as they are needed by the source. However, shortest-hop based routng s not sutable for wreless sensor networks snce t neglects the energy ssue. We ncluded proposed metrc n the Zgbee routng protocol AODV routng protocol. Thus, our new verson of AODV chooses the most effcent path to the destnaton node by consderng energy, delay and buffer capacty. Applyng the Metrc: Before sendng the data to the snk, a node must start the route dscovery process to create a neghbor lst, whch s the address of all nodes that are able to transmt data from the source. Durng ths process route request and reply messages are exchanged between the nodes. The route request message as shown n Fgure 2. The RREQ packet s enhanced wth two addtonal felds, a packet recepton rate (PRR) and Max effcency. Intermedate nodes calculate PRR and effcency from eq. () and eq. (2) upon recevng a RREP packet. Intal value of PRR s set to. After establshng the path between the snk and the source the routes are stored n a routng table as shown n Table to allow future queres for the allocated paths. The routng table stores nformaton about the paths that can be used to drect data messages and verfy the valdty of each table record. When a destnaton node receves a RREQ packet t wll process t and sends back a RREP packet on the reverse path. In order to choose the route, ths s a effcent path. Destnaton should not reply to the frst route request whch receved. Instead, t should wats for a set amount of tme and compares the delvered RREQs then sends a route reply by selectng an approprate route. Fg. 3: Packet delvery rato vs. number of nodes Smulaton Results: In ths secton we evaluated performance of proposed algorthm and compared t wth the AODV algorthm and Improved AODV algorthm. We have changed the exstng mplementaton n NS-2 of AODV to ntegrate our metrc. Thus, we have a new verson of AODV, whch we call AODV wth new metrc. It s compared to the Aodv protocol and the Improved AODV n [7]. The smulated networks consst of 0, 20, 00, 200 nodes respectvely. Evaluaton parameters that consdered for our algorthm are: Packet Delvery Rato: Ths s rato of the total receved packets to the total sent packets n the sensor network. The delvery ratos of the routng protocols ncrease as the node densty ncreases. Fgure 3 shows the Packet delvery rato wth network traffc rates. From the fgure t can be seen that the Packet delvery rato of AODV algorthm and mproved AODV are less than that of call AODV wth new metrc. In fact, n small sensor network there s almost one path from the source to destnaton. Thus, the routng algorthms choose the same path. However, for a network wth a larger number of source nodes, the Improved AODV performs better than AODV and modfy AODV does. Average Delay: The average delay measures the average tme between sendng data from sources to recevng data by snks over all source-snk pars. It ndcates the feasblty and effectveness of the protocol. Fgure 4 depcts when the number of node s low all algorthms wll have the same routng choces. Snce valdaton of paths s almost equal, but when traffc ncreases, the dfference between these routng algorthms appears. The proposed algorthm selects paths wth the lower delay. 570
Fg. 6: Interested packet attrbutes Fxed Attrbutes Snk ID Applcaton Context (type, operator, value) ISeqNum Flow ID Varable Attrbutes PrevousHopID V L gradents PPR Hop count Max effcency Fg. 4: Average delay vs. number of nodes Fg. 7: Neghbor nformaton entry Neghbor Id VL IseqNum Breakage flag Gradent Hop Count PPR Maxeffcency Lowest-latency-gradent ETE_Delay(only for tradtonal DDflter) Fg. 5: Energy consumpton vs. number of nodes Energy Consumpton: The average energy consumpton s calculated across the entre topology. It measures the average dfference between the ntal level of energy and the fnal level of energy. Ths metrc s mportant because the energy level that a network uses s proportonal to the network s lfetme. Fgure 4 show at the begnnng the two routng approaches have the same result. In fact, n the begnnng all nodes have a maxmal amount of energy. When the number of nodes ncreases, the average energy consumpton proposed algorthm s less than AODV algorthm and mproved AODV. We extend AODV routng protocol usng the proposed metrc. Smulaton was performed wth varyng network characterstcs, the results depcted gans n throughput n terms of packet delvery rato, reducton delay and optmze consumpton energy especally when a large number of nodes exsted. Fgure 5 demonstrates ths effect. However, AODV algorthm s a specal algorthm n ad hoc network, t doesn t work effcently for sensor network when network s dense so we focus on specal algorthm n wreless sensor network. Applyng the Metrc on Drect Dffuson: In ths secton, we wll study the detals on how to set up gradents and descrbe PRR flter to extend drected dffuson. At last, we make smulaton respectvely wth those two dfferent gradents setup algorthms and make a comparson between them. PRR Flter: PRR flter s realzed by settng up correspondng gradents, whch s performed when recevng nterest packets. In drected dffuson algorthm, snk node sends nterest message for a query. PRR flter s recognzed by the related gradent when the ntal nterest messages are receved. The nformaton contaned n an nterest packet s shown n Fgure 6. Fxed attrbutes n fgure 6 specfy whch sources and snks communcate. Whenever a snk ntates the new nterest floodng perodcally, t wll ncrement ts counter, ISeqNum. The fxed attrbutes are not changed whle propagated across the network. On the other hand, when an ntermedate node broadcasts an nterest packet, t wll change varable attrbutes. But varable attrbutes are changed by ntermedate nodes. PrevouseHopID varable n the nterest packet represents the neghbor, where t receved the message. Intermedate node calculate PRR and Max effcency from eq. () and eq. (2) when receves nterest packet. Hop count counts hope that the packet passed from source to ths node. 57
Fg. 8: PRR gradent setup pseudo code Intermedate Node Handles Interest packet Step : Get Informaton from nterest packet: SnkId, IseqNum, PrevousHopID,HopCount,V L,Max effcency Step 2: Fnd NIE n NIT accordng to the PrevousHopID NIT: Neghbor Informaton Table NIE: Neghbor Informaton Entry Step 3: In the NIE, update gradent Step 4: Decde whether the Interest should be broadcast or not calculate current effcency: case: frst tme to receve the Interest {Max effcency = current effcency Next hop node = ths node Hc = hop count} case 2: f (current effcency > max effcency ) {Max effcency = current effcency Next hop node = ths node Hc = hop count} case 3: f( (current effcency = max effcency ) and hop count< hc) {Next hop node = ths node Hc = hop count} Step 5: If one of the above three cases happens, update Interest packet and broadcast t Settng up the PRR Gradent: PrevousHopID n the nterest packet s the ndex of the correspondng neghbor nformaton entry (NIE) whch s shown n Fgure 7. The collecton of NIEs s called neghbor nformaton table (NIT). The ID s the unque dentfcaton of the neghbor. When an ntermedate node receves an nterest packet, frst t wll look at the nformaton contaned n the nterest packet. When a node receves the frst nterest packet, t sets up PRR gradent to the sender node and calculates PPR and path effcency from equaton (2), then assumes the sender node as the next hop and updates ts NIE n NIT. When a node receves other nterest packets, frst calculates path effcency, f the new nterest path effcency s less than the current effcency, the node gnores that nterest packet, but f the nterest path effcency s greater, t adopts the new sender as the next node. Because of PRR value, t s very unlkely that the nterest packets have the same valdty. Even f they have the same valdty, ntermedate node selects an nterest packet wth smaller Hop count. Intal value of PRR s set to. Fgure 8 shows a setup pseudo code for PRR gradent. In ths algorthm, we use the method n for local Reparng n the case of nodes breakage n durng of routng. If MAC feedback nformaton ndcates that transmttng a data packet to the next hop node fals, the ntermedate node wll mark the next hop node broken n neghbor nformaton entry. The ntermedate node wll flood a BreakageNotfcaton packet. When the snk receves the BreakageNotfcaton packet, t wll ntate nterest floodng mmedately to update stale gradents over the network. We assume that there s a retransmsson mechansm based on acknowledgement packets n meda access control (MAC) protocol for relablty. If a predetermned number of retransmsson fals, the MAC layer nforms ths falure to the upper layer []. Table 2: Smulaton parameters confguraton Smulaton area scale 200 m 200 m Topology confguraton model Randomzed Each node buffer 50 packet Intal node energy 4500 Watt. Sec Interest packet sze 32 byte Tme nterval that snk floods nterest packet 300s Number of nodes 200 Sensor Data Packet Payload 28 byte The Smulaton Model: In ths secton we evaluated performance of proposed algorthm and compared t wth the standard Drected Dffuson algorthm and proposed algorthm n [9]. We use NS-2 smulators to mplement the physcal and MAC layers of IEEE 802. We have changed the exstng mplementaton n NS-2 of Standard Drected Dffuson to ntegrate our metrc. Thus, we have a new verson of Drected Dffuson, whch we call Improved Drected Dffuson. for smulaton be used of snk but number sourees are dfferent n senaruoes. The parameters we used n our smulaton are shown n Tables 2. In our sensor network model two hundreds of sensor nodes are randomly dstrbuted on a 200 m *200 m area. The sensor nodes are battery-operated except the snk node. The maxmum transmsson range of sensor node s 5 m. Sensor nodes have a low moblty that s the case for most of the sensor network applcatons. The snk node wll ntate nterest floodng (ndcates a new task) perodcally. We assume the delay needed to transmt a packet from a source node to a destnaton node s equvalent to the number of hops counted between these two nodes. We deploy an energy model accordng to the power consumpton parameters n [0]. The delay needed to transmt a packet from a source node to a destnaton node s equvalent to the number of hops counted between these two nodes. Also we wll consder many-toone communcaton wth one snk and several sensor nodes reportng data to the snk. 572
Fg. 9: Average node energy vs. tme Fg. 0: Packet loss rato vs. number of sources Evaluaton Metrc: Evaluaton parameters that consdered for our algorthm are: Energy Consumpton: In ths secton, nodes energy consumpton n the proposed algorthm wll be dscussed. To study the consumpton of energy of nodes, the proposed algorthm s named mproved. It s compared to the drected dffuson protocol and the modfed algorthm wth proposed metrc n [9]. Numbers of source nodes are consdered as 2, 6 and 2 nodes. The smulaton tme s 500 seconds, average energy consumpton s calculated every 00 seconds and node's energy s set to 00 Watt. Fg. : Average packet delvery vs. number of nodes Energy model and parameters n smulaton of the proposed algorthm s assumed as an orgnal drected of the nterest and dscovery packets whch occupy dffuson code and the requred sendng and recevng bandwdth. Ths s an obstacle to receve data packets to energy s 0.666 Watt for sendng and 0.395 watt for the central node. recevng data based on energy consumpton n PCM-CIA WLAN n ns2 smulator. Average Packet Delay: In ths secton, average packet The smulaton s performed n the three scenaros. In delay s dscussed. To calculate ths parameter, the the frst scenaro, number of source node s 2. The average delay of png packets from to 5 sources wll be average energy consumpton n the proposed algorthm s calculated. Smulaton tme s set to 500 seconds. Fgure 5% and 2% more than the drected dffuson protocol n llustrates the average packets delay n ths scenaro. the frst and the second scenaros respectvely. Number The average packet delay of the proposed algorthm s 6% of the nodes n the thrd scenaro s set to 2. Node's less than the drected dffuson protocol. In ths fgure, energy consumpton n ths case s shown n the Fgure 9 when the number of source nodes are low, then the packet and the average consumpton of nodes n the proposed delay n the two algorthms are almost the same. algorthm s 22% further than the drected dffuson Furthermore, route credt polces are equal. Increasng the algorthm. Lower energy consumpton of the proposed number of source nodes s cause to lower delay due to ts algorthm s due to assortng selecton of the ntermedate credt polcy of route selecton. nodes. CONCLUSION Packet Loss: Route packet loss s explanatory of the route fault tolerant. Fgure 0 shows that the In ths paper a method of ntermedate nodes packet loss n the proposed algorthm s 8% less selecton durng the routng process wll be proposed. than the drected dffuson protocol. Proper selecton Ths method s based on credt assgnment of neghbor of routes causes lower packet loss n the proposed nodes. Amount of remaned node's energy, buffer sze of algorthm. The man reason of the packet loss s floodng node and lnk qualty are the parameters whch are used to 573
calculate credt. The related neghbor's credt of each node 3. Boughanm, Yeqong, N., 2007. A New Routng s stored n a table and the tables wll be updated durng Metrc for Satsfyng Both Energy and Delay the data sendng and recevng. At last, the node wth the Constrants n Wreless Sensor networks, The journal hghest credt s selected to forward data. Ths metrc of VLSI Sgnal Processng, Sprnger New York, cause to data traffc dstrbuton between nodes justly and 5: 37-43. used ablty most network nodes also t caused to we hold 4. Intanagonwwat, C., R. Govndan, D. Estrn, J. global routng algorthms of nformaton about routes. Hedemann and F. Slva, 2003. Drected Dffuson for Every node n ther table keeps nformaton valdty related Wreless Sensor Networkng, IEEE/ACM to neghbor node. Fnally between neghbors nodes, Transactons on Networkng, (). selected one node wth hgh valdty. Smulaton results 5. Levs, P., S. Madden, D. Gay, J. Polastre, R. Szewczyk, show that the proposed algorthm cause to lower energy A. Woo, E. Brewer and D. Culler, 2004. The consumpton, lower packet delay and reduced packet loss Emergence of Networkng Abstractons and n comparson wth the drected dffuson protocol. Albet Technques n TnyOS, Proceedngs of the Frst n case of network's traffc ncreasng, the proposed USENIX/ACM Symposum on Networked Systems algorthm s more effcent because of ts capablty to use Desgnand Implementaton, NSDI 2004. equally all nodes n the routng process and data 6. Mn, R.A.F., M. Do Val Machado, A.A.F. Lourero forwardng. and B. Nath, 2004. Predcton-based energy map for For future work It s supposed that nodes have no wreless sensor networks, Ad Hoc Networks Journal. moblty n ths paper, so moblty can be consdered and 7. Perkns, C.A., E.M. Royer and S.R. Das, 0000. Ad-hoc Regardless of supposng one snk n the proposed on-demand dstance vector routng, IETF Internet algorthm, the effect of mult snk can be studed also In Draft of AODV, Verson 0. ths paper, a lnear traffc model s utlzed to study the 8. Zgbee Specfcatons, 2004. http://www.zgbee.org. route effcency, so n future works ths parameter can be 9. Chpara, O., Z. He, G. Xng, Q. Chen, X. Wang, C. Lu, used n dfferent traffc models. J. Stankovc and T. Abdelzaher, 2006. Real-Tme Power-AwareRoutng n Sensor Networks, REFRENCES Fourteenth IEEE Internatonal Workshop on Qualty. Henzelman, W., A. Chandrakasan and H. of Servce (IWQoS 2006). 0. Bhaskar Krshnamachar, Deborah Estrn, Stephen Balakrshnan, 2000. Energy effcent communcaton Wcker, The Impact of Data Aggregaton n protocol for wreless mcro-sensor networks, In Wreless Sensor Networks, cdcsw, pp.575, 22nd HICSS, pp: 3005-304. Internatonal Conference on Dstrbuted Computng 2. Sohrab, K., B. Manrquez and G. Potte, 999. Near- Systems Workshops (ICDCSW '02), 2002. ground wdeband channel measurements, IEEE. Chen, M., T. Kwon and Y. Cho, 2005. Energy- Proceedngs of Vehcular Technology Conference, effcent dfferentated drected dffuson (EDDD) New York. for real-tme traffc n wreless sensor networks, Computer Communcatons. 574