TSEEC - TS/TDMA based Energy Efficient Congestion Control in Mobile Wireless Sensor Network

Transcription

1 , October 19-21, 2011, San Francsco, USA TSEEC - TS/TDMA based Energy Effcent Congeston Control n Moble Wreless Sensor Network Sohal Jabbar, Awas Ahmad, Ataul Azz Ikram, Murad Khan Abstract In past few years, a remarkable change has been faced n the feld of wreless sensor network moble sensor nodes. Congeston n the network and lmted energy causes delay n the network. Due to ths very reason, t has been now an oblgatory to ensure the approprate use of the gven resources. Savng the battery lfe, sagactc tme allocaton, mnmzng the communcaton delay, effectve congeston control and n some aspect managng the entrance and ext of nodes n a specfc cluster s the key ssue to be satsfed n an algorthm clamng to be effcent congeston control protocol for a moble wreless sensor network. To deal wth the sad confront, we proposed Congeston Control Protocol (CCP) for Moble Wreless Sensor Network. It uses the exstng TDMA technque wth combnaton of Statstcal Tme Dvson Multplexng (STDMA), wth enhanced newly proposed technque of Tme-Sharng TDMA (TS-TDMA) to avod congeston, saves energy and provdes effcency. Smultaneous effort of approachng the target not only causes the data loss due to congeston ssue but also results n squeezng the energy whch ultmately comes up wth reducng the network lfe tme. We have mplemented our work on Network Smulator (NS-2.27). The smulaton results shows that TSEEC performs well to avod congeston, saves energy and reduces delay n the network. Key Words: TS/TDMA, Congeston Control, CCP, STDMA I. INTRODUCTION Wreless Sensor Network uses a shared medum and the sensor nodes send data to ther neghborng nodes as well as to the cluster head at the same tme. Hence there are chances of creatng congeston resultng n energy wastage on the nodes as well as on the cluster head of the WSN. Sensors are the montorng and survellance devces manly consstng of sensng, processng, storage and power subsystems, deployed over a large geographcal area dependng upon the applcaton requrements. Ths dosyncratc technology of Manuscrpt receved Jul 15, 2011; revsed August 14, Correspondng authors: Sohal Jabbar s PhD Scholar under supervson of Dr. Abd Al Mnhas at Department of Appled Scences and Graduate Studes, Bahra Unversty Islamabad Pakstan (sabbar.research@gmal.com) Awas Ahmad s wth Department of Appled Scences and Graduate Studes, Bahra Unversty Islamabad Pakstan (Emal: awas.ahmad@lve.com) Ataul Azz Ikram s Head Of Department, Dept. of Computng and Technology (Emal: ata.ul.azz@gmal.com) Murad Khan s wth Iqra Unversty Islamabad, Pakstan (Emal: muradkhan23@gmal.com) wreless sensor network has ts applcaton n Glacer montorng [1], volcano montorng and tunnel montorng and rescue, snper localzaton, ocean water and bed montorng, rescue of avalanche vctms, trackng vehcles, wldlfe montorng, cattle herdng, vtal sgn montorng and cold chan montorng [2]. Energy s an mportant resource for WSNs and t plays an mportant role n communcatng nformaton packets between dfferent nodes n the network. Congeston n WSN s ether Node Level or Lnk Level. Former s caused by the overflow of node buffer due to the lack of capacty to store further packets. Later s due to too much nformaton packets beng sent on the channel by varous neghborng nodes. The nnovatve technque of TS- TDMA hybrd-protocol s a useful remedy for controllng both these traffc congestons, whch s dscussed n subsequent sectons: The STDMA uses a technque of statstcal measurement of the data load and energy requrements on each moble node, thereby helpng the moble nodes send data to the recever wthout NLC. The moble nodes share nformaton about ther respectve unque ID, packet load, energy level and locaton wth the statc Cluster Head; Usng the feedback from the nodes and the TDMA technque, the Cluster Head assgns tme slot to dfferent moble nodes; TS-TDMA (Tme-Sharng TDMA) s our new nnovatve technque that helps the moble nodes share ther allotted tme-slots among themselves dependng on whether a moble node has sensed any data or not. Cluster Head remans the coordnator. There are several defcences n the wreless sensor network where moble nodes are ultmate n the stuaton. Dfferent nodes move n zgzag drecton. Jonng and leavng clusters and communcate wth Cluster Head and neghborng nodes s a dffcult task. It causes dlemma of acqurng the channels as well as tme slots to avod congeston on snk node. In such condtons, many-to-one node communcaton establshes whch causes collson of packets [3]. Collson of packets leads consumng of extra energy for retransmttng of same packets. Whle workng on MAC layer, energy schemng s an mmense ssue. Huge amount of energy wasted when a node receve many packets from dfferent resources. So the destnaton node wll drop extra packets and the source node wll waste ts energy by sendng extra packets. We need such algorthm, whch preval over the lmtatons of the mentoned algorthm. The proposed

2 , October 19-21, 2011, San Francsco, USA algorthm, TSEEC mnmzes delay, avod congeston and mprove effcency of the network. The algorthm s tested wth dfferent traffc load n the network and showed our result n secton IV. Secton II comprses Lterature Survey, Secton III ncludes our proposed Network Model, and Secton IV s specfed for our proposed algorthm results. II. LITERATURE SURVEY There s always a room for mprovement. A commodty that s once consdered as 100% n ts demand s devalued to nothng later. Exstng protocol to control conservaton of energy, delay n the network and congeston n moble wreless sensor network are so n addressng ths problem. Congeston at cluster head creates overhead whch entals consderable amount of energy, packet loss and delay n the network. A network that s free from these lls must be able to assgn tme slots to dfferent moble nodes n the zone, and n each tme slot a partcular node should be actve for communcaton and performng the assgned task. There are varous protocols to avod congeston n wreless networks lke CSMA/CA n IEEE protocol for CR-WPAN whch s used to cover beacon enable mode n [3]. Cross layers termnology s used n order to share nformaton between dfferent protocol layers whch helps n ncreasng nterlayer nteractons. In ths scenaro one maor ssue has been found.e. nteracton of MAC and transport layer operaton results n collson as well as congeston are the maor problems n the source packet loss. Packet collson due to many-to-one traffc pattern under heavy traffc loads s dscussed n [4]. Energy effcent MAC protocol has been proposed, where, there are full sleep cycle at dfferent leaf nodes whch helps n mnmzng the load on leaf nodes n heavy traffc. In such envronment, the leaf node goes n to full sleep state for one complete cycle, ths leads to reducton of packet collson as well as reduce the consumpton of energy whch saves at low depth nodes. Robust Routng Algorthm wth Far Congeston Control (RRA-FCC) s presented n [5]. Ths algorthm s used for mnmzng the congeston at the snk node. Snk s a node to whch two or more devces send data at a tme, the challenge s the congeston. RRA-FCC s used to control congeston and thereby reserve energy for the network. A typcal wreless sensor network conssts of one or two snk nodes, but new research technques now enable to deploy tens to thousands of snk nodes n a regon. If we compare ths wth Ad- Hoc Network, the followng characterstcs have been notced. Lmted resources: lmted resources nclude energy processng capacty as well as memory to store sensed data. Low moblty: the general scenaro of WSN ncludes statc nodes however; there can be very few nodes whch can move n the envronment. Data centrc: data sensng s an mportant feature of WSN. The data has been sensed wthout knowng the IDs of whch the nodes set the data [5]. Several MAC protocols for wreless sensor network are dscussed and evaluated n [6]. It has been notced that by sensng and sendng data from one node to another node or from one node to the cluster head consumes consderable energy as compared to the computaton of data by sensor nodes or cluster head. Demkol et al. have also dscussed the factors that results n energy wastage at MAC layer. The mportant factor s congeston on snk node, where more than one node sends data at tme, whch results n droppng of the packet. After that, source needs to resend that amount of data agan. Ths retransmsson needs extra energy consumpton. Overhearng s a process when one node receves extra packets that are not requred. It means that the data has been broadcast over the network for one specfc node but other nodes also receve the same data as unwanted or extra packet. Idle lstenng s the process when the node s lstenng to a channel when dle that results n ncrease of traffc n the network. The last reason s over metng. Ths can be done by sendng packet to that node whch s not ready for ntake of the packet. To avod such crcumstances, a MAC layer protocol s requred preserver extra energy. Therefore, the proposed protocol named TSEEC whch deals wth the above mentoned drawbacks of the network. Varous protocols and algorthms regardng delay and congeston n the wreless sensor network n [7]. It dentfes lmted battery power as the man ssue n wreless sensor network functonng. As already dscussed, wreless nodes have lmted battery power. If deployed n an envronment where rechargng of these batteres s dffcult or mpossble, the WSN could fal. In TDMA based MAC protocol, tme slots have been arranged n sequence and assgned to each frame. TRAMA s the most mportant protocol used for energy effcency and avod collson n channel [8]. TRAMA s the TDMA based approach whch splts the tme nto two parts.e. random access protocols and scheduled access perod. Whle deployng wreless sensor nodes n any physcal envronment, the assgnment of cluster head s an mportant task. III. PROPOSED SOLUTION It s a dffcult ob to control congeston on the snk node n WSN due to always broadcast transmsson nature. Although transmsson s broadcast yet decodng can be uncast. Therefore, t s requred to desgn MAC protocol wth specal focusng on congeston control. Ths ultmately results prolong network lfetme. In partcular, our proposed soluton deals wth the energy conservaton, delay and effcency of the network. Tme Sharng-Tme Dvson Multple Access Protocol s presented as the mproved verson of TDMA, whch also havng the workng features of STDA a. Overvew Let us consder a sensor network consstng of n moble nodes deployed n x,y coordnates. Deployed topology conssts of moble sensor nodes grouped together n the form of clusters wth statc cluster head. Interested nodes to

3 , October 19-21, 2011, San Francsco, USA on the cluster are authentcated by the cluster head usng dstance rato between ther neghborng cluster heads. Jonng nodes are then assgned the tmeslots through Statstcal Tme Dvson Multple Access (STDMA) technque. Memory status (load of sensed data) and crtcalty of locaton of the respectve moble node are the tme slots assgnment parameters. ST/TDMA based Energy Effcent Congeston Control n Moble Wreless Sensor Network (TSEEC) specfcally targets the ssues lke delay, energy wastage, congeston and neffcent network. Two man strateges are there under the umbrella of TSEEC to cope up wth the delay ntroduced due to freeng up of allocated Tmeslots and above mentoned ssues: Load Based Allocaton (LBA) strategy and Tme Allocaton Lester (TAL) strategy. LBA s purely based on STDMA method of tme slot allocaton. The three fold nature of Tme Allocaton Lester (TAL) manpulates the free tme slots arse due to moble nodes onng and leavng the zone. Three modules n the paradgm of TAL assst ths workng that are, ) Extrcated Tme Allocaton (ETA) ) Shft Back Tme Allocaton (SBTA) ) escaped Tme Allocaton (STA). TAL has been used n order to provde effcency and to overcome the ssue of delay ntroduced caused by dfferent moble sensor nodes due to congeston on cluster head. The synergstc matng of STDMA and TAL strateges come up wth the reduced energy consumpton, effectvely and effcently tme allocaton, lessenng the communcaton delay between node and the cluster head and sagactc congeston control between the node and cluster/zone head. Overvew of TSEEC workng s also depcted n Fgure 1` b. Cluster Head Electon Explotng the self organzng capablty of sensor nodes, each node may know ts neghborng nodes as well as ts Cluster Head (CH). As the deployment s determnstc, so at ntal stage, selecton of CH s on hand. Due to the homogenous nature of nodes, the node havng the more neghbors s desgnated as Cluster Head (CH). Cluster Head s the man head of the cluster. Each node attaches tself to the CH on the bass of receved sgnal strength (RSSI). If a node receves nvtaton from more than one Cluster Heads then the followng crtera s followed: Sweght Sweght Where Sweght s weght or strength of receved sgnal of the nvtee CH. If Sweght Sweght Then the selecton s on the bass of Eweght Eweght Where Eweght s the weght of energy level of nvtee VH. If Eweght Eweght Then a random selecton s made. c. Load Based Allocaton Load Based Allocaton s mplemented on the true essence of statstcal tme dvson multple access (STDMA) technque. Status of memory and locaton s shared by the member nodes to the Cluster Head (CH). The node havng less memory (more data to be transmtted/more sensed data) and of more crtcal locaton s assgned the tme slots relatvely. Ths assgnment procedure s followed n the start and on the entrance of node to the zone. Although Moblty of the nodes makes ths tme slots assgnment process somewhat more burdensome to the cluster head, yet t s properly managed by the LBA n collaboraton wth TAL. TAL keep control of the free tme slots and assgn accordngly from the CH end. d. TS/TDMA Tme Sharng-Tme Dvson Multple Access s a technque of Hybrd nature. LBA s purely based on STDMA method of tme slot allocaton. Assgnment of tme slots to the cluster members s assgned by consderng the load of. After the cluster head formaton, the moble nodes send ther locaton, memory and energy values to CH. Assgned tme slots are based on prorty precedence order of ) memory ) battery and ) locaton. e. TAL Strateges The three-fold nature of TAL strategy manpulates the effects arsng out of moble nodes onng and leavng the zone. The three prongs of TAL are: Extrcated Tme Allocaton (ETA), Shft Back Tme Allocaton (SBTA) and Escaped Tme Allocaton (STA). () ETA: ETA handles the stuaton when there s no sensed data to be transmtted by non-cluster head and the assgned tme slot s consdered free. Tme freeng up by the sensor due to the absence of sensng consders two scenaros for ts utlzaton: a. Assgnng the free tme slots by the CH to the new entrant of the zone to partcpate n the communcaton process b. Assgnng the free tme slots by the CH to the exstng neghbor node of the free node. Ths technque wll occur when moble sensor node has no data to sense. Sometmes, t can also happen that when moble node senses the same data, so t s requred not to send the redundant data. Then t broadcast the message for ts neghbor to shft back tme slot as per empty tme slot whch has been left over due to no sensng or redundant data. At the same tme, when newly arrved moble node ons the cluster, so t wll also broadcast ts arrval to the cluster head, the remanng tme slot wll be allotted to newly arrved moble node. So bascally, tme freeng up by the sensor node due to the absence of sensng n a scenaro or redundant data, where a moble enterng the zone and there s no moble enterng the zone s handled by ETA. () SBTA: It happens when moble node leaves the current cluster. Frst t wll broadcast ts leavng state as well as

4 , October 19-21, 2011, San Francsco, USA tme slot to ts cluster head, and wll enters to ts neghborng cluster. The neghborng cluster head wll a lot tme slot as t were left over due to ETA. So SBTA conduces the tme released due to the node leavng the zone n the same scenaro as of ETA. () STA: The ncomng node whspers the lnk and updates the CH2 about ts status of new entrant. CH2 manages the tme n the followng way: a. Wat for completng the duty cycle of assgned tme slot to the cluster member nodes. And then assgn the tme slot to the new entrant based on the same crtera as was followed n the start of workng of algorthm. b. Assgn the saved tme slot taken from the unused to the new entrant. Ths strategy asssts n tme savng as well as energy conservaton. Free tme slots are avalable due to ) Leave of node ) Death of node ) No sensed data to be transmtted Hence the assgned tme slot become free from ther rearrangng by the nserton to the cycle for the new entrant or to the neghborng node by shftng ther startng tme of arranged tme slot back. General workng of SBTA s as follows. (a) If (a node has no data) (b) Then (c) t alert to cluster head (d) Cluster head shftback T of other nodes by a factor of t +1, t +2 (e) node (T of node ) (t +1 + t +2 ) Load (HTR) and a Hybrd Protocol of SMAC and n, whch nfluence overall network effcency and avod congeston. In our smulaton on NS2.27, we have consdered smulaton tme of 50 seconds wth smulaton area of 1000m*1000m and deployed 50 moble sensor nodes. The maxmum packet sze for transmsson s 100 bytes. In our smulaton, we have used two ray ground propagaton model whch consders the drect path as well as reflected path. There are two clusters n our scenaro; each cluster has 25 moble nodes wth statc cluster head. Each sensor node has 15J of energy. Dfferent moble nodes communcate through wreless channel. We have consdered MAC type and n n our scenaro n order to accomplsh better results n has typcally used for energy reservaton and congeston control. Wreless sensor nodes operate on batteres. One of the common applcatons of wreless sensor network s envronment montorng. We have deployed moble sensor nodes n adhoc manner. Due to ts lmted power, perodc and aperodc has been consdered of awake and sleep state, whch s based on our sad protocol of TSEEC. The man applcaton of MAC that we can dfferentate t from customary Wreless MAC -e has the energy conservaton and congeston control whch are the prmary goals. The use of n has been mplemented on cluster head so that t may communcate wth all sensor nodes wthout any congeston and also savng ts energy. All moble sensor node communcate through ther antenna. In our smulaton, we have used Omn-drectonal antenna, because t has to propagate sgnals n all drecton n equal power Deployment of Moble Sensor Nodes In Fgure 2, all the moble sensor nodes arranged themselves nto cluster. Before sensng any data, the nodes send ther locaton nformaton, battery lfe tme to cluster head to form approprate cluster for requrement of tme slots wth the help of STDMA. In ths Fgure there are 2 clusters, each wth 25 moble sensor nodes. Here, all the moble sensor nodes busy n sensng data. TDMA technque wll be appled wth the help of cluster head. The moble sensor nodes frst sense data and then forward t to cluster head as shown as n Fgure 2. Fgure1: Moble node leavng ts zone and enterng to neghborng zone IV. SIMULATION AND RESULT DISCUSSION For performance evaluaton of our proposed algorthm, TSEEC, Network Smulator (NS-2.27) s used. In our smulaton, we have calculated energy consumpton per node, Delay n Low Traffc Load (LTR) and Hgh Traffc Fgure 2: Deployment of Moble Sensor Nodes

5 , October 19-21, 2011, San Francsco, USA We performed smulaton n three aspects wth the same smulaton parameters as dscussed n frst part of secton IV and n table 1. Experment 1 shows the energy consumpton n (Joules) by each moble sensor node. The comparson of perodc and aperodc sleep schedule has been consdered Experment 2 gves us the result of energy consumpton by the cluster head wth the mplementaton of n. The energy consumpton has been acqured from dfferent states -e transmttng state, recevng state, lstenng state, sleep state and dle state. Experment 3 shows the comparson of two protocols embeddng n our proposed algorthm of TSEEC -e SMAC and n EXPERIMENT 1: The graph n Fgure 3 llustrates that wth smultaneous employment of perodc-sleep-state and TS-TDMA technques (as aganst the tradtonal TDMA technque) ndvdual nodes consume much less energy. Energy problem n sensor nodes s crtcal. It also saves the energy. The sad algorthm deals wth the above mentoned problem n the best way. It s cleared from the graph that the deployment of sensor nodes n perodc state gves us half good results as compared to a perodc state. In a perodc state, the sensor nodes are alve for long perod of tme and ths provdes productve results. Energy remaned balanced due to perodc state and we have followed ths algorthm n our proposed model of TSEEC. However wth aperodc state, very lmted amount of energy as well as sensor node s n resdual. Fgure 3: Energy Consumpton n each sensor node EXPERIMENT 2: We have mplemented n at back end.e. on cluster head n order to calculate ts energy level. All the nodes have 15 Joule energy; wthn that energy they have to communcate throughout the entre sesson. From the graph n Fgure 4, Cluster Head consumes less energy on communcatng wth one partcular sensor node. (Transmttng to one partcular sensor node), although CH consumes average energy whlst lstenng to all nodes as well as newly arrved node n that cluster. On the other hand, n recevng state, t shows that CH consumes much hgher energy due to recevng of maxmum number of data from dfferent nodes, newly arrved node n the cluster, processng of data and assgnng of tme slots to newly arrved tmeslots n STA case. Fgure 4: Energy status of IEEE n Consumed energy = Total Energy - Sum of energy n all states. C e = T E T S C e = 15J 9.2J C e = 5.8J C e s the level of energy consumpton of our entre scenaro. EXPERIMENT 3: Ths graph n Fgure 5 shows the delay n n and SMAC. We have mplemented two dfferent protocols n cluster (Sensor nodes and Cluster Head). We have confgured n on cluster head and around those sensor nodes SMAC s beng confgured. In SMAC protocol and IEEE n, consderable amount of delay has been found; combnng these two protocols n our network sgnfcantly reduces ths delay. The combne energy consumpton of the cluster head and moble sensor node s beng decreased. Hence we can prove from the above graph that hybrd network along wth TS-TDMA consumes less energy, has average latency and hgh effcency, whch helps n prolongng the network lfe tme wthout delay and congeston.

6 , October 19-21, 2011, San Francsco, USA Fgure 5: Delay/Tmngs n Hybrd Network From the above three experments, t s concluded that deployment of moble sensor nodes n any area wth the mplementaton of our proposed TSEEC protocol shows better results whle calculatng energy level by comparng dfferent attrbutes as well as mplementaton of n and SMAC n our scenaro. The resultant hybrd protocol on ts mplementaton n clustered based sensor network topology gves effcent results wth respect to above mentoned performance parameters n part paragraph of secton IV V. CONCLUSION In ths paper, we have dscussed varous avalable technques regardng congeston control, latency, delay and energy consumpton n WSN. We have also mplemented the nnovatve technque of TS-TDMA hybrd-protocol to avod congeston, reduce both delay and the resultant energy defcency. Secondly, allocaton of tme slots and sharng of tme slots amongst dfferent moble nodes and load balancng technque helps n mnmzng memory as well as extra energy wastage. The synergstc matng of TDMA wth Tme Sharng algorthm and STDMA results n energy consumpton, effectve and effcent tme allocaton, lessenng communcaton delay between node and the cluster head, and sagacous congeston control. We have mplemented our work on moble sensor nodes wth statc cluster head. We have seen ts results after mplementaton on NS-2.27 and for dervng graphs usng GNUPLOT functon has been made use of. TS-TDMA has been found to be the most suted soluton to deal wth maor bottlenecks n WSN communcaton.e. congeston, latency, energy consumpton, delay on moble nodes and cluster heads and overall effcency of the network. [2]. R. Rem-Vs, Cold chan management usng an ultra low power wreless sensor network. Boston, USA: WAMES 2004, June [3]. Radosveta Sokullu, Cagdas Donertas Combned effects of moblty, congeston and contenton on network performance for IEEE Based Networks. Computer and Informaton Scence, 2008, ISCIS 08, 23 rd Internatonal Symposum on Dgtal Obect Identfer: /ISCIS Publcaton Year 2008, Page(s): 1-5. [4]. Kyoungseok Oh, Seok Woo, Seokn and Kseon Km Improved energy effcency of DMAC wt perodc full sleep cycle for WSN wth heavy traffcs Intellgent Sensors, Sensors Networks and Informaton, 2007, ISSNIP 2007, 3 rd Internatonal Conference on Dgtal Obect Identfer /ISSNIP Publcaton year: 2007, Page(s): [5]. Yunlu Lu, Yuheng Lu, Juhua Pu and Zhang Xong A robust routng algorthm wth far congeston control n WSN. Computer Communcaton and Networks, 2008, ICCCN 08. Proceedngs of 17 th Internatonal Conference on Dgtal Obect Identfer: /ICCCN.2008.ECP.167. Publcaton year: 2008, Page(s): 1-4. [6]. Ilker Demkol, Cem Ersoy and Fath Alagoz MAC protocols for WSN: A Survey. Network Research Laboratory (NETLAB) of Computer Engneerng Department of Bogazc Unversty, Bebek, Istanbul, Turkey. [7]. Guseppe Anastas, Marco Cont, Maro D Francesco and Andrea Passarekka Energy conservaton n WSN: A Survey. AdHoc Networks 7 (2009) Journal [8]. V.Raendran, J.Garca-Luna Aceves, Energy-effcent collson-free medum access control for wreless sensor networks n: proc. ACM SenSys 2003, Los Angeles (USA) November 2003 REFERENCES [1]. H. K. Martnez and J. Stefanov, Glacsweb: A sensor web for glacers. Berln Germany: EWSN 2004, January 2004.