Simulator for Energy Efficient Clustering in Mobile Ad Hoc Networks

Transcription

1 Smulator for Energy Effcent Clusterng n Moble Ad Hoc Networks Amt Kumar 1 Dhrendra Srvastav 2 and Suchsmta Chnara 3 Department of Computer Scence and Engneerng, Natonal Insttute of Technology, Rourkela, Orssa, Inda. 1 Amtkcs036@gmal.com 2 Dheerendra.ntr@gmal.com 3 suchsmta@ntrkl.ac.n ABSTRACT The research on varous ssues n Moble ad hoc networks s gettng popular because of ts challengng nature and all tme connectvty to communcate. Network smulators provde the platform to analyse and mtate the workng of the nodes n the networks along wth the traffc and other enttes. The current work proposes the desgn of a smulator for the moble ad hoc networks that provdes a test bed for the energy effcent clusterng n the dynamc network. Node parameters lke degree of connectvty and average transmsson power are consdered for calculatng the energy consumpton of the moble devces. Nodes that consume mnmum energy among ther 1-hop neghbours are selected as the cluster heads. KEYWORDS Moble ad hoc networks, Smulator, clusterng, energy consumpton. 1. INTRODUCTION Moble ad hoc networks support the communcaton among the nodes when they are on the fly. Moblty of the nodes n and around the network causes frequent change n the network topology. Thus the change n network topology that s assocated wth the lnk falures and creatons perturbs the routng stablty. Along wth that, the scarce n rado resources and bandwdth, lmted battery power and computng capablty pose challenges n MANET scalablty and effcency [1, 2]. In such scenaro, the role of smulator to analyse the varous paradgms of the network plays a vtal role. There exst some smulators for such a dynamc network lke ns2, OPNET, Qual Net, GloMo Sm, OMNeT++ etc. To understand the characterstcs of a dynamc network along wth the node moblty patterns, the paper presents the desgn of a smulator for the moble ad hoc networks that forms clusters n the network. In conventonal cellular network the moble nodes communcate drectly wth the fxed base staton reducng the wreless part of communcaton to a sngle hop problem. Thus the mappng of cellular archtecture nto peer to peer network leads to the concept of clusterng [6]. In such a vrtual cellular archtecture (VCA) cluster heads are selected to play the role of base statons of cellular network. The cluster head along wth ts one-hop members form the vrtual cells retanng the merts of cellular structure. The process of cluster formaton deals wth parttonng the network nto logcal groups called clusters. The cluster head wthn each cluster that acts as the Davd C. Wyld, et al. (Eds): CCSEA, SEA, CLOUD, DKMP, CS & IT 05, pp , CS & IT-CSCP 2012 DOI : /cst

2 192 Computer Scence & Informaton Technology (CS & IT) local coordnator for ts member nodes also guarantees for faster communcaton [3]. The cluster head n every cluster does the resource allocaton to the cluster members and les responsble for nter-cluster communcaton. Cluster heads beng the communcaton hotspots tend to dran ts battery power rapdly whle servng ts member nodes [8]. Further, energy consumpton s a key factor that hnders the deploy ablty of a real ad hoc and sensor network. It s due to the lmted lfe tme of the battery powered devces that motvates ntense research nto energy effcent desgn of operatng systems, protocols and hardware devces. The rest of the paper s organzed as follows. Secton II descrbes the work done n the related area. Secton III descrbes the desgn of the proposed smulator and the clusterng algorthm for the selecton of cluster heads. Secton IV depcts the smulaton scenaros and the results assocated wth the algorthm for the cluster formaton. Fnally secton V concludes the paper. 2. RELATED WORK Network smulators are used by researchers, developers and engneers to desgn varous knds of networks, smulate and then analyze the effect of varous parameters on the network performance. A typcal network smulator encompasses a wde range of networkng technologes and can help the users to buld complex networks from basc buldng blocks such as a varety of nodes and lnks. Smulaton s a technque where a program models the behavor of a network ether by calculatng the nteracton between the dfferent network enttes lke nodes, lnks and packets usng mathematcal formulas, or actually capturng and playng back observatons from a producton network. Most of the exstng smulators are GUI drven. The network parameters descrbe the state of the network lke node placement and exstng lnks and the events lke data transmssons and lnk falures etc. The exstng smulators provde the test bed to carry out the mplementaton of the network protocols. The smulator GloMoSm s desgned usng the parallel dscrete event smulaton capablty provded by a parallel programmng language Parsec that support protocols for purely wreless networks. OMNeT++ s a component based, modular and open-archtecture dscrete event smulaton framework. Every smulator has ts own pros and cons. The concept of parttonng of the random dynamc network nto logcal clusters (also called as the Lnked Cluster Archtecture LCA) was ntally proposed by Baker and Ephremdes [7]. The exstng one-hop clusterng algorthms emphasze ether on mnmzng number of cluster heads [1, 2]) n the vrtual back bone to reduce the routng delay or maxmzng the cluster stablty by un-alterng the head nodes [3,7]. A small varaton to LCA was proposed by Ephremdes, Weselther and Baker n [3] as a lowest ID algorthm. In ths algorthm a node havng lowest ID among ts neghbors s selected as the head node. It retans ts utlty as a benchmark for producng reasonably stable cluster control archtecture as dscussed by Gerla and Tsa n [1]. However, as node ID s the only decdng factor for a node to be a cluster head, the lower ID nodes are based to become the heads all the tme resultng n ther faster energy dranage whch may perturb the cluster stablty. A modfed verson of LCA was proposed by Parekh [2] that ams to reduce the number of clusters n the network. If { N } represents the set of neghbors of a partcular node, then the degree of connectvty of s represented as D = N, where N s the cardnalty of{ N }. A hgher degree of connectvty ensures lower delay n communcaton through cluster heads. The

3 Computer Scence & Informaton Technology (CS & IT) 193 moblty of nodes changes the degree of connectvty of the node very frequently whch leads to more number of cluster head reelectons as well as lnk updatons resultng poor cluster stablty. A moblty metrc based verson of lowest ID algorthm MOBIC was proposed by Basu, Khan and Lttle [14]. The algorthm uses moblty based metrc for calculaton of weghts of the nodes by usng the rato of two consecutve sgnal strengths receved by a node to know ts relatve moton wth respect to ts neghbors. When two cluster heads accdentally come wthn ther transmsson range, re-clusterng s deferred for Cluster_Contenton_Interval (CCI) perod as per the LCC [4] algorthm. Though MOBIC provdes a better cluster stablty, but the need to collect relatve speed nformaton of a node from ts neghbors degrades ts performance. The author n [4,9]) proposed a weght based dstrbuted moblty adaptve algorthm DMAC that removes the non-moblty assumpton of the hosts durng clusterng setup and mantenance. However, when two head nodes come wthn the transmsson range of each other; the node wth the lower weght has to resgn ts role as head and s forced to become the member node of the node wth hgher weght. The combned metrc clusterng algorthms [5, 10, 12] use some node parameters lke runnng average, degree of connectvty or mean connectvty, transmsson power, avalable battery power or consumed battery power to fnd ts sutablty as a head. But obtanng so much of nformaton to compute the combned weght for every node n the network needs a longer frozen perod of moton before the cluster s actually formed. A large number of message exchanges take place globally to yeld the node wth lowest weght. The authors of [16] have proposed a topology adaptve clusterng algorthm TACA. As the network s actvated, clusters are formed wth the electon of volunteer cluster heads. When any of these volunteer head drans a threshold amount of ts battery power then t selects a nonvolunteer head wthn ts own cluster so that t can hand over the responsbltes to the newly selected head locally. Ths avods as much as possble to a global cluster head electon procedure that demands consderable computaton and communcaton overhead. 3. PROPOSED SIMULATOR FOR CLUSTERING ALGORITHM 3.1. Bascs of the Smulator The moble ad hoc network can be modelled as a undrectonal graph G = (V, L) where V s the set of moble nodes and L s the set of lnks that exst between the nodes. We assume that there exsts a bdrectonal lnk L j between the nodes and j when the dstance between the nodes d j < range t (transmsson range) of the nodes. In the dynamc network the cardnalty of the nodes V remans constant, but the cardnalty of lnks L changes due to the moblty of the nodes.

4 194 Computer Scence & Informaton Technology (CS & IT). Fgure 1: Smulator for dynamc network depctng the nodes n the network. Fgure 1 depcts the smulator where nodes are randomly deployed n a 100X100 smulaton area. Each node s dentfed wth a unque dentfer ID as shown n the fgure. The nodes n the network are allowed to move freely wthn the network area by followng the Random Way Pont Moblty model (RWP) and satsfy the boundary condtons. In the RWP the nodes chooses a random speed and random drecton and moves towards the destnaton. After reachng the destnaton t pauses for a whle before selectng another set of speed and drecton for the next movement [RWP]. Whle movng n the network the nodes establsh connectvty wth the neghbor nodes that are wthn ther transmsson range. Fgure 2: The smulator after the nodes probed ther connectvty wth the neghbours. Fgure 2 depcts the lnks establshed by the neghbor nodes n the network. The node wthout havng any lnks wth other nodes s called as the solated node. In the fgure there exsts an solated node. The lnks among the nodes may change as the nodes move from ther poston.

5 Computer Scence & Informaton Technology (CS & IT) Selecton of Cluster Heads n the Smulator The proposed work s a modfcaton to the work done by the authors of [16]. The energy effcent clusterng algorthm s a dstrbuted algorthm. It consders the battery power consumed by a node and ts average transmsson power utlsed for servng ts neghbors as the parameters to decde ts sutablty for a cluster head. These two parameters are added wth dfferent weght factors to fnd the weghts of the ndvdual nodes. The steps for fndng the cluster heads n the network are descrbed below: Step 1: Every node probes ts neghbors by broadcastng hello packets and recevng acknowledgements from others. Fgure 2 represents the nodes after fndng ther connectvty n the network. Step 2: The nodes calculate the number of neghbors from whch t receves the acknowledgements. Ths number represents ts degree of connectvty D or the cardnalty of the node n graph theory termnology. Step 3: Compute the average transmsson power utlzed by a node as: Dst P av = where D P av = Average Transmsson Power. Dst = Dstance between the node and ts one hop neghbors. Step 4: Compute the weght of the node as W = α * E + β * Energy cons P av Where α and β are the weght factors and Energy P = Energy consumed due to the average transmsson power utlsed. av The algorthm ndcates that a node havng lowest weght W among ts 1-hop neghbors consumes mnmum battery power and utlses mnmum transmsson power to serve the neghbors. So ths node s selected as the cluster head and ts 1-hop uncovered neghbors (.e. whose role s not yet decded) become the cluster members of the selected head. The set of covered nodes are exempted from takng part n subsequent selecton procedure and ths process s repeated tll all the nodes are assgned wth ther role ether as a head or a member. The example of cluster setup phase of the proposed algorthm s demonstrated wth the help of Fgure 3.

6 196 Computer Scence & Informaton Technology (CS & IT) Fgure 3: Cluster heads are dentfed n the smulator. Fgure 4 represents the smulator showng the degree of connectvty, average transmsson power and the energy consumed by every node n the network. Ths table gets updated wth the occurrence of changes n the network scenaro. Fgure 4: Smulator depctng the connectvty, energy consumed by the nodes. 4. CONCLUSIONS A network smulator s a software program that predcts the behavour of a network wthout the actual network beng present. In smulators, the computer network s typcally modelled wth devces, traffc etc and the performance s analysed. Typcally, users can then customze the

7 Computer Scence & Informaton Technology (CS & IT) 197 smulator to fulfll ther specfc analyss needs. The proposed smulator s developed to mplement a dstrbuted clusterng algorthm for ad hoc networks. A node that consumes mnmum energy among ts one-hop neghbors s selected as the cluster head. The heads get changed as ther weghts change n the network. The change n the network scenaro s reflected n the table for ready reference. REFERENCES [1] M.Gerla and J.T.C.Tsa, multcluster, moble,multmeda rado network, wreless networks, 1,3,pp ,1995. [2] A. K. Parekh, Selectng routers n ad hoc wreless network, Proceedngs of the SBT/IEEE nternatonal telecommuncaton symposum, August [3] D.J.Baker, J.E.Weselther and A. Ephremdes, A desgn concept for relable moble rado networks wth frequency hopng sgnalng, proceedngs of IEEE, vol. 75, no.1, Jan [4] S.Basagn, Dstrbuted and moblty-adaptve clusterng for multmeda support n mult-hop wreless networks, proceedngs of vehcular technology conference, VTC, vol.2, pp , [5] S.Das, M.Chatterjee, D.Turgut, Wca: A weghted clusterng algorthm for moble ad hoc networks, Journal of Cluster computng (specal ssue on moble ad hoc networks), vol. 5, no. 2, 4, pp , [6] S. Basagn, I. Chlamtac, A. Farago, A generalzed clusterng algorthm for peer-to-peer networks, Proceedngs of Workshop on Algorthmc aspect of communcaton (satellte workshop of ICALP), July [7] D.J.Baker and A. Ephremdes, The archtectural organzaton of a moble rado network va a dstrbuted algorthm, IEEE Transactons on Communcatons COM-29, pp , 11(Nov.1981). [8] J.H.Chang and L.Tassulas, Energy conservng routng n wreless ad hoc networks, Proceedngs of INFOCOM 2000, Tel-Avv, Israel, March [9] S. Basagn, Dstrbuted clusterng for ad hoc networks, Proceedngs of Internatonal Symposum on Parallel Archtectures, Algorthms and Networks, pp , June [10] S.Das, M.Chatterjee, D.Turgut, An on demand weghted clusterng algorthm(wca) for ad hoc networks, n proceedngs of IEEE GLOBECOM 2000, pp , San Francsco, Nov [11] T. Ohta, S. Inoue, Y. Kakuda, An adaptve clusterng scheme for hghly moble ad hoc networks, n proceedngs of sxth nternatonal symposum on autonomous decentralzed systems(isads 03), Aprl [12] We-dong Yang and G-z Zhang, A weght-based Clusterng Algorthm for moble Ad Hoc Network, proceedngs of Thrd Internatonal Conference on Wreless and Moble Communcaton (ICWMC 07), [13] S. Basagn, M. Cont, S. Gordano and I. Stojmenovc, Moble ad hoc networkng, A John Wley & Sons Inc. publcaton, [14] P. Basu, N. Khan and T.D.C. Lttle, A moblty based metrc for clusterng n moble ad hoc networks, Proceedngs of IEEE ICDCS 2001 workshop on wreless networks and moble computng, Phoenx, AZ, 2001.

8 198 Computer Scence & Informaton Technology (CS & IT) [15] R. Ghosh and S. Basagn, Lmtng the mpact of moblty on ad hoc clusterng, Proceedngs of the 2nd ACM nternatonal workshop PE-WASUN 05, Montreal, CA, pp , [16] Suchsmta Chnara and Santanu Kumar Rath, Taca: A Topology Adaptve Clusterng Algorthm for Moble Ad Hoc Networks, Proceedngs of WORLDCOMP Internatonal Conference on Wreless Networks (ICWN 09), July 14 th -17 th, Las Vegas, USA, pp , Authors Amt Kumar s persung hs B. Tech degree n Computer Scence Engneerng n the Natonal Insttute of Technology Rourkela. The current work s a part of hs thess work carred out n hs fnal year. Dhreendra Kumar s persung hs B. Tech degree n Computer Scence Engneerng n the Natonal Insttute of Technology Rourkela. The current work s a part of hs thess work carred out n hs fnal year. Suchsmta Chnara s workng as an Assstant Professor n the Department of Computer Scence Engneerng at Natonal Insttute of Technology Rourkela. Her area of nterest ncludes wreless networks.