Advanced LEACH: A Static Clustering-based Heteroneous Routing Protocol for WSNs

Transcription

1 Advanced LEACH: A Statc Clusterng-based Heteroneous Routng Protocol for WSNs A. Iqbal 1, M. Akbar 1, N. Javad 1, S. H. Bouk 1, M. Ilah 1, R. D. Khan 2 1 COMSATS Insttute of Informaton Technology, Islamabad, Pakstan. 2 COMSATS Insttute of Informaton Technology, Wah Cant, Pakstan. ABSTRACT Wreless Sensors Networks (WSNs) have a bg alcaton n heterogeneous networks. In ths aer, we roose and evaluate Advanced Low-Energy Adatve Clusterng Herarchy (Ad-LEACH) whch s statc clusterng based heterogeneous routng rotocol. The comlete network feld s frst dvded nto statc clusters and then n each cluster searate Ad-LEACH rotocol s aled. Our roosed rotocol s nherted from LEACH wth a cluster head selecton crtera of Dstrbuted Energy- Effcent Clusterng (DEEC). Ths enables Ad-LEACH to coe wth the heterogeneous nature of nodes. Due to small statc clusters, each node reduces ts broadcast message ower because t only has to cover a small area. We erform smulatons n MATLAB to check the effcency of Ad-LEACH. The Smulaton results show that Ad-LEACH outerforms LEACH and DEEC n energy effcency as well as throughut. KEYWORDS: Wreless Sensor Networks, DEEC, LEACH, Ad-LEACH I. INTRODUCTION The technologcal advancements n the feld of hardware desgn and system on ch has enabled the desgners to create mnute wreless sensors whch erforms many DSP oeratons[1] [10]. These sensors are autonomous objects, whch are vastly deloyed n random fashon n the requred regon. Ther number can vary from dozens to many thousands accordng to requrement. They can rovde a hgh qualty and fault tolerant network caablty [13-18], however ther battery lfe tme s lmted. Ths ncreases the use of Wreless Sensor Networks (WSNs) n varety of alcatons. From crtcal medcal alcatons to battlefeld survellance, the demand of WNSs s ncreasng radly. The legacy centralzed algorthms need a comrehensve knowledge of entre network. Whenever, there s an error n transmsson or n case any crtcal node des, there are a lot of chances that the rotocol reaches the bottleneck [2]. The awful and dynamc envronment of WSN ncreases the chances that a node can lose ts connecton from network. Thus, ncreases the bottleneck robablty of centralzed algorthm. On the other hand, dstrbuted algorthms are based on sngle node whch do not requre global knowledge of the network. Therefore, a falure of sngle node does not affect the system crtcally. Ths makes the localzed algorthm more robust and scalable. Due to the nature of WSN, each node s tghtly ower constraned. Therefore, the entre network has lmted lfe tme. To extend the network lfe, an energy effcent routng rotocol s requred. Many routng aroaches have been roosed to extend lfe tme of battery. Clusterng s one of them n whch nodes are organzed nto searate clusters. Ths aroach leads to an energy effcent soluton. The rotocols roosed n [3] and [4] rovde energy effcent routng soluton by effcently organzng cluster formaton. Data aggregaton can be executed wth the hel of clusterng technques [5] [6]. The large data comng from many nodes s comressed by usng data aggregaton technques. Therefore, a small amount of ackets are transmtted whch contans meanngful nformaton, ths leads to an energy effcent soluton. Clusterng technque s of great mortance n WSN. It s very effcent n data query and broadcast of messages [7] [8]. Ether broadcastng a message or collectng useful nformaton wthn a *Corresondng Author: Nadeem Javad, COMSATS Insttute of IT, Islamabad,

2 Iqbal et al.,2013 cluster, Cluster Head (CH) s of enormous hel. The clusterng algorthms lke Low-Energy Adatve Clusterng Herarchy (LEACH) [6], Hybrd Energy Effcent Dstrbuted (HEED) clusterng aroach [11] and Power-Effcent Gatherng n Sensor Informaton Systems (PEGASIS) [12] suose WSN as homogeneous, whch s the reason behnd ther falure n heterogeneous scenaros. In ths aer, we resent a new routng scheme for heterogenous networks, whch s more effcent than already roosed schemes; LEACH and DEEC. Ths scheme nherts the characterstcs of LEACH and DEEC. We erform extensve smulatons n MATLAB to verfy the effcency of our new scheme; Ad-LEACH, n WSNs. II. MOTIVATION LEACH [6] rotocol rooses that each node should elect tself as a CH, therefore, frst CH selecton rocess s ntated. After the selecton of CH, there s a cluster formaton hase. After all nodes assgn themselves to ther resectve CH, each CH allocated a tme slot to ts clent node. All nodes use that allocated tme slot to communcate wth ts resectve CH. The stochastc CH selecton algorthm s used n LEACH s roosed for homogeneous networks. CH s a node whch collects data from all ts clent nodes, comress t and then transmt t towards Base Staton (BS). Durng ths whole tme erod, CH consumes extra energy. The node selected as CH des out quckly due to extra energy burden. It s roosed n LEACH that all nodes n network share ths load. To dvde ths addtonal load unformly for all nodes, LEACH rooses that every node s = (1,2,3.. N) becomes CH after 1/ rounds [6]. Ideally t s a good soluton, however, as the network evolve the energy level of all nodes dffer due to dfferent traffc load and ther dstance from BS. Ths leads to unfar CH selecton and nodes wth low energy des out quckly. Fg. 1. CH selecton crtera of LEACH s gven from [6]: fs G 1 T s) = 1 ( rmod ) n 0 otherwse ( (1) A novel scheme s roosed n ths aer whch s nherted from LEACH [6]and DEEC [9]. By also takng the legacy statc clusterng nto consderaton a rotocols s formed whch s an energy effcent heterogeneous routng soluton.

3 III. NETWORK MODEL In ths secton, the network model s elaborated. The tye of network s heterogeneous. There are N tot numbers of nodes, randomly dstrbuted across X Y regon. Each cluster contans N number of nodes. The dstrbuton of each N s random where the value of can vary from 1 to q, here we have taken q=4. The man regon s further dvded nto sub regons whch are normally referred to as, clusters. The formaton of each cluster can be square, rectangular or both accordng to network desgn requrement. Ths tye of network deloyment s deal for the scenaros where the hyscal arameters of geograhcal area are known, esecally for survellance of hgh value laces. Fg The nodes are always transmttng data to BS.As shown n Fg. 1 the locaton of BS s n the center of man regon. Fg. 1 (a) shows that all nodes communcate wth ther resectve CH s. Each CH receves data from all of t s clent nodes and erform some necessary teratons for comresson. Fg. 1 (b) shows that only CH s communcaton wth Base Staton. All CH s forward the comressed data to Base Staton. As, t s suosed n [10] that all nodes are consdered nomadc or statonary wthn ther resectve cluster. Therefore, there s no abrut change n network toology. There are two tyes of network on the bass of energy; homogenous and heterogenous. In former tye of network, nodes havng same energy levels are deloyed, whereas, n lateral tye, nodes ossess dfferent ntal energy levels. The heterogeneous network are consdered n our work. We dvde network nto two energy levels of nodes. The nodes wth hgher energy level are called advanced nodes and the nodes wth low energy level are called normal nodes. The ercentage of advanced nodes s m. Each advanced node osses a tmes more energy then a normal node. The ntal energy of each cluster s equal to E, usng two levels E. Energy comutaton for clusters, of energy n [6] s gven as: E = NE0(1 m) + NmEo a) (2) where, E 0 s the ntal energy of normal node and total quantty of normal nodes s (1 m)n. The advanced nodes are N m n number and ther energy s E o a). N c ls reresents the quantty of nodes resent n current cluster. Therefore, after manulaton we get the energy of each cluster as: E = NE0 am) (3) The summaton gves us the total ntal energy of whole area: where, q = total number of clusters. E total q = E (4) =1 IV. PROPOSED PROTOCOL In ths secton, we dscuss our roosed Ad-LEACH n detal. Ad-LEACH s rmarly based on statc clusterng. The locaton of BS and clusterng formaton of the entre network s redefned. IV.1 CLUSTER FORMATION In Ad-LEACH, durng the establshment of network the whole area s alenated nto ermanent and statc clusters. The shae of clusters can be square or rectangular accordng to the desgn requrement and area avalable. Durng our smulaton we found almost dentcal results of both rectangular and square shae clusters. Each cluster contans a searate Ad-LEACH rotocol runnng n arallel to ts neghborng clusters. The nsraton n the wake of searatng the whole area nto small statc felds s to reduce comlexty and ower dssaton. Small ortons of clusters are easy to manage rather than one large feld of oeraton. In ths way, the nodes also reduce the ower level of ther broadcast messages

4 Iqbal et al.,2013 because they only have to cover a small orton of area from the man regon. IV.2 CLUSTERS HEAD (CH) SELECTION Runnng a searate Ad-LEACH nto all clusters means that each cluster has ts own CH. DEEC s roosed n [9], whch takes the heterogeneous characterstcs of WSNs nto consderaton. Ths results n mroved scalablty and a reduced amount of battery consumton. In order to acqure more defntve soluton, we choose CH selecton algorthm of DEEC n our Ad-LEACH rotocol The DEEC soluton chooses CHs based on ther resdual energy. Each node requres rerequste knowledge of network lke total energy and network lfe tme. In DEEC, BS broadcasts the total energy of network E total to all nodes. The BS also estmates the value of R whch s network lfetme and broadcast t to all nodes. In the start of every new eoch, all nodes calculate the value of usng the equaton (5) whch s taken from [9], as: broadcasts the total energy of network E total to all nodes. The BS also estmates the value of R whch s network lfetme and broadcast t to all nodes. In the start of every new eoch, all nodes calculate the value of usng the equaton (5) whch s taken from [9], as: = ot N N a) N + ae ( r) =1 Here N s total number of nodes resent n current cluster. The value of E (r) s calculated n equaton(6)[9], as: 1 r = Etotal (1 ) (6) N R Let the energy consumed by network n each round s denoted by E round then the estmated value of R s calculated wth equaton (7) [9]. Etotal R = (7) Eround Now each node uses the value of and ut t n equaton number (8) to get the value of T ( s ) [9]. The value of T ( s ) s used by every node to decde f t s CH n current round. fs G T ( s ) = 1 ( rmod1/ n) (8) 0 otherwse After a node s selected as CH, t must kees ts rado recever turned on so all clent nodes to nform the CH about ther exstence. In order to do that Carrer Sense Multle Access (CSMA) MAC rotocol s used n ths hase by all clent nodes. (5) IV.2.1 PROBABILITY OF HETEROGENEOUS NODES The equaton (9) [9] dctates that ot s the reference value of. In heterogeneous network the reference value of every node dffer from each other accordng to ts ntal energy value. E ( r) = ot (9)

5 As two level heterogeneous network s consdered n ths research we wll use modfed values of as gven n equaton (10) and (11). [9] ot Ths changes the value of adv nrm ot = am) ot a) = am) and we get equaton (12). ote ( r) fs = normalnode am) ot a) E ( r) = fs = advancenode am) (10) (11) (12) As we consdered two level heterogeneous network n our research we wll use modfed values of as gven n equaton (10) and (11). ot IV.2.2 CLIENT SCHEDULING The CH receves the clent nformaton from each node. The CH creates a Tme Dvson Multle Access (TDMA) schedule for all of ts clent nodes and broadcast t back to all nodes. ths TDMA schedule s used by all clent nodes to transmt ther data towards CH node. IV.2.3 DATA TRANSMISSION After all clent nodes receve ther TDMA slot nformaton, the rocess of data transmsson begns. All clent nodes only communcate to CH durng ther assgned tme slot. In order to save the energy each clent node turned off ts rado durng unallocated tmeslots. The nodes le near to CH transmt low energy sgnal and as the dstance ncreases between clent node and CH the transmsson energy of each node ncreases. Each clent node chooses ts own transmsson energy level, based on Receved Sgnal Strength (RSS) of the CH advertsement message. When a CH receves data from all of ts clent nodes, t erforms some necessary sgnal rocessng technques on ths data to comress t. After comresson, ths data s transmtted towards BS. Durng ths whole rocess the rado nterface of CH remaned turned on, whch consumes energy. When CH transmts nformaton towards BS, t s also hgh energy transmsson. Ths leads to the fact that beng a CH uts a lot of energy burden on each node. That s the man reason behnd rotatng CHs durng whole network oeraton. SIMULATION RESULTS The erformance of Ad-LEACH s scrutnzed n ths secton usng MATLAB. A heterogeneous WSN contanng n = 100 nodes s consdered n ths smulaton. The value of m = 0.1 whch means there are 10% advanced nodes contanng a tmes more energy than the normal nodes. The smulaton area s X = 100m Y = 50m whch creates a rectangular feld. All nodes are dsersed around ths feld randomly. Table. 1 shows the rado arameters used n ths smulaton. Table 1: Smulaton Parameters Parameters Values

6 elec Iqbal et al.,2013 E 5 nj/ bt ε J fs 10 /bt/ m ε m J /bt/ m E 0 0.5J E 5nJ/bt/message d DA m Message Sze 4000 bts P 0.1 ot 2 2 In two-level heterogeneous network, LEACH and DEEC s comared wth our roosed Ad- LEACH. Fg. 2,3 and 4 show the results usng m = 0.1 and a = 0. Fg. 2. Energy Consumton n Selected Protocols Fgure 2 shows the result of energy consumton comarson er round between LEACH, DEEC and Ad-LEACH. The results dects that LEACH consumes more energy and reaches the threshold value of 50 joules between 1000 and 1500 rounds. The erformance of DEEC rotocol s better than LEACH and t reaches the 50 Joule mark n almost 2200 rounds. Our roosed Ad-LEACH rotocol s better than both LEACH and DEEC because of less energy consumton and t reaches the threshold n around 3150 rounds. Fg. 3 shows the total number of lvng nodes er round and Fg. 4 shows total number of dead nodes er round. The results from these two grahs show that nodes de out n LEACH quckly and n around th 1500 rounds all 100 nodes de out whereas the frst node des near 1000 round. The frst node of DEEC des after 1500 rounds and the death of last node occurs at 3500 rounds. The Ad-LEACH shows very romsng result here as the death of frst node s occurrng after 2300 rounds and the last node des after 5000 rounds.

7 Fg. 3. Comarson of Alve Nodes n Selected Protocols Fg. 4. Comarson of Dead Nodes n Selected Protocols Stablty erod of any rotocol s when all of ts nodes reman alve. After the death of frst node tll the death of last node, s consdered the unstable erod. Table (2) comares the unstable and stable regons of LEACH, DEEC and Ad-LEACH. Table 2: Stable and Unstable Regon Comarson of LEACH, DEEC and Ad-LEACH Protocol LEACH DEEC Ad-LEACH Stable regon 1000 rounds 1500 rounds 2300 rounds Unstable regon 500 rounds 2000 rounds 2700 rounds Network Lfetme 1500 rounds 3500 rounds 5000 rounds The throughut comarson s shown n Fg. 5. The fgure shows that the throughut of Ad- LEACH s hgher than both LEACH and DEEC. In ths scenaro we changed the values of m and a. The change n these values changed the throughut of Ad-LEACH and DEEC because they both consder the heterogeneous nature of nodes. ths change does not affect the erformance of LEACH as t s urely desgned for homogenous nodes.

8 Iqbal et al.,2013 Fg. 5. Throughut Comarson when m = 0.1 and a = 0 Fg. 6. Throughut Comarson when m = 0.5 and a = 4 V. CONCLUSION In ths aer, we roose a new rotocol; Ad-LEACH for WSNs. Ths s an energy effcent routng rotocol whch s based on legacy statc clusterng aroach. In our roosed scheme, CH selecton mechansm s nherted from DEEC whereas, rotocol archtecture s adoted from LEACH rotocol. To valdate the erformance effcency of our roosed scheme, smulatons are erformed n MATLAB. The selected erformance metrcs are: throughut, energy consumton, number of dead and alve nodes. Smulaton results valdate the erformance effcency of Ad-LEACH n the case of two level heterogeneous networks, as comared to LEACH and DEEC. Therefore, we conclude that Ad-LEACH s more sutable for heterogenous WSNs. REFERENCES 1. M. Aslam, N. Javad, et al., Survey of Extended LEACH-Based Clusterng Routng Protocols for Wreless Sensor Networks, 5th Internatonal Symosum on Advances of Hgh Performance Comutng and Networkng (AHPCN-2012)n conjuncton wth 14th IEEE Internatonal Conference on Hgh Performance Comutng and Communcatons (HPCC-2012), June 2012.

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