Research on Data Reliable Transmission Based on Energy Balance in WSN

Transcription

1 Sensors & Transducers, Vol. 7, Issue 5, May 04, pp Sensors & Transducers 04 y IFSA Pulshng, S. L. hp:// Research on Daa Relale Transmsson Based on Energy Balance n WS Yongxan SOG, Rongao ZHAG and Zhuo SHE School of Elecronc and Informaon Engneerng, Jangsu Unversy, Zhenjang, 03, Chna School of Elecronc Engneerng, Huaha Insue of Technology, Lanyungang, 000, Chna E-mal: soyox@6.com Receved: 7 Feruary 04 /Acceped: 30 Aprl 04 /Pulshed: 3 May 04 Asrac: In vew of energy load uneven dsruon of WS, some nodes wll de premaurely due o excessve energy consumpon, whch lead o nerrupon of communcaon lnks and daa packe loss, hus relale daa ransmsson s affeced. On he ass of analyzng he man facors ha affec energy consumpon and exsng energy savng echnologes, comned wh applcaon of vrual mulple-npu mulple-oupu (Vrual MIMO) roung algorhm n somorphc wreless sensor nework, vrual mulple-npu mulple-oupu cluserng algorhm (VMMCA) whch apples o small and medum scale somorphc WS s proposed. VMMCA no only can selec cluser head randomly, u also can acheve he lfe cycle opmzaon of WS on he premse of assurng nodes communcaon qualy. Vrual MIMO cluser nework energy consumpon model s esalshed. On he condon of changng for dfferen clusers sze, node dsruon densy, he pah loss ndex and snk nodes, he change of he energy consumpon of vrual MIMO nework and nework s analyzed. In order o alance nework energy load and prolong lfeme of WS, and he nework lfeme s aken as he opmzaon arge, he rao of he clusers head s opmzed y genec algorhm. The expermen and smulaon resuls show ha compared wh LEACH algorhm, VMMCA can acheve very good alance of energy and prolong nework lfeme. Copyrgh 04 IFSA Pulshng, S. L. Keywords: Cluserng algorhm, Vrual mulple-npu-mulple-oupu (MIMO), Energy effcency, Load alancng.. Inroducon Wreless sensor nework s an negraed nellgen nformaon sysem ha s composed of low cos and energy consraned sensor nodes y way of selforganzaon, he relale daa ransmsson s compleed under he jon acon of each node, f one node wll de due o runnng ou of aery energy, can affec nework connecvy and produce daa packe loss, so ha relale daa ransmsson slowdowns n performance, he node wll ecome he lmng facor for relale nework daa ransmsson, hs phenomenon s called shor oard effec n wreless sensor nework. In order o prolong he lfe of WS, s very mporan o desgn low power consumpon srucure and energy effcen roung algorhm of nodes. Mulple-npu Mulple-oupu (MIMO) echnology reaks hrough he prolem of lmed channel capacy n he radonal sngle npu sngle oupu () wreless communcaon sysem[], and when he communcaon dsance exceed a ceran hreshold, compared wh, energy consumpon of MIMO s less. Reference [] proposed MIMO nodes srucure and communcaon sraeges for heerogeneous WS, he resuls shown ha hs mehod was superor o nework n he aspecs of energy consumpon and laency. MIMO no only has complex ransmsson crcu, u also 68 hp://

2 Sensors & Transducers, Vol. 7, Issue 5, May 04, pp need o have powerful sgnal processng aly, and sensor nodes are lmed y he volume and energy, so s no realsc o nsall mulple anenna [3]. Wh he rapd developmen and ncreasngly maure of MIMO echnology, more and more researchers sudy vrual MIMO echnque [4]. Sudes shown ha compared wh ransmsson or mulple hops, vrual MIMO echnology no only consdered he addonal crcu ranng cos and energy consumpon, and s effcency was hgher [4-6]. Reference [4] effecvely avoded energy consumpon n cluser daa roadcas process y vrual MIMO mul-cas ransmsson, and nework parameers wh mnmal energy consumpon were deermned hrough jon opmzaon sysem. The smulaon resuls shown ha he lfe cycle of nework have sgnfcanly ncreased n dfferen cases. Bu he algorhm needs o furher explore how o choose he opmal nework srucure and he approprae cooperaon nodes. Reference [7] pu forward a knd of daa ransmsson scheme ased on vrual MIMO echnque scheme n wreless sensor nework, alhough hs scheme can reduce he nework energy consumpon, he ranng energy consumpon of choce collaorave cluser heads and encodng complexy wll e ncreased due o adop vrual mulple npu sngle oupu (MISO) echnology n daa gaherng sage. In order o furher reduce energy consumpon n Reference [8], daa fuson and collaorave communcaon were effecvely comned, and elmnaed daa redundancy eween he nodes. The opmal cooperaon nodes selecon, he energy dsruon eween source nodes and collaoraon nodes were suded n Reference [9], u he nfluence of opmal cluser head proporon and nework scale was no consdered. Based on he aove analyss, accordng o he characerscs of homogeneous WS, comne he energy alance of LEACH algorhm and he characerscs of vrual MIMO echnology, and pu forward a knd of vrual mulple npu mulple oupu cluserng algorhm (VMMCA). In order o effecvely reduce he nework energy consumpon, prolong nework lfe cycle, and mprove nework daa relale ransmsson, vrual MIMO echnology and dynamc energy savng echnology are appled o he enre nework n VMMCA algorhm. In order o make he energy load average assgned o each node, he vrual MIMO cluser head nodes are eleced n urn, as o avod premaure deah of cluser nodes ha have he large energy consumpon due o he excessve consumpon, so he nework lfe cycle s prolonged. On he condon of changng for dfferen clusers sze, node dsruon densy, he pah loss ndex and snk nodes, he change of he energy consumpon of vrual MIMO nework and nework s analyzed. In order o alance nework energy load and prolong lfeme of WS, and he nework lfeme s aken as he opmzaon arge, he rao of he clusers head s opmzed y genec algorhm. The expermen and smulaon resuls show ha compared wh LEACH algorhm, VMMCA can acheve very good alance of energy and prolong nework lfeme.. WS Model Based on Vrual MIMO For he pas few years, wh he connuous developmen of MIMO wreless communcaon sysem, and formed a communcaon means ased on vrual MIMO [0]. Tha s o say, each mole ermnal of communcaon sysem ased on Vrual MIMO no only has a sngle anenna, u also has one or more parners for cooperaon ransmsson, and no only ransm s own nformaon u also ransm s parners' nformaon, s shown n Fg. [3]. Vrual MIMO ranscevers are composed of cooperave mole ermnals, whch form a vrual mul-anenna srucure. Each ermnal ransm nformaon jonly y channel space of her own and s parners, so more spaal dversy gan s oaned and sngle-anenna mole ermnals spaal dversy s mplemened. So he vrual MIMO communcaon sysem no only can ncrease channel capacy, u also can mprove nework servce qualy and sysem performance. Because of he resrcons of qualy, volume and energy consumpon, for WS nodes, s very dffcul o mplemen mul-anenna srucure. Fg. shown ha a sngle anenna node ased on vrual MIMO can ge he mul-anenna spaal dversy gan. Supposed ha each sendng node has a se of daa o e sen o he recevng node, he sender nodes roadcas s own nformaon o s parners y TDMA, and he sendng ermnal have all parners' daa n he local communcaon process. A sngle node s seen as an anenna of vrual anenna array, he encoded daa s ransmed o he recevng ermnal n parallel y he sendng ermnal n he long range communcaon process. Fg.. Vrual MIMO ransmsson. On he ass of srucure of vrual MIMO communcaon, amng o he homogeneous WS nework, a vrual MIMO cluser algorhm (VMMCA) s proposed, he nework srucure s shown n Fg. [3]. A vrual MIMO ranscever s composed of M nodes, and nework ermnals are dvded no several clusers, each cluser has a vrual MIMO cluser head whch consss of M nodes, and 69

3 Sensors & Transducers, Vol. 7, Issue 5, May 04, pp he local clusers ermnal nformaon whch has colleced s ransmed o Snk ode (S) y vrual MIMO Cluser Head (VCH). On he ass of cluser-heads-random- selecng echnology n a crcular paern whch s adoped y LEACH, comnng vrual MIMO echnology, and akng he characerscs of somorphsm WS no consderaon, VMMCA can e proposed as follows.. Inalzaon. S roadcas nalzaon nformaon o all nodes, namely, adversemen of snk (AOS), he node operang parameers are nalzed, and ID deny nformaon of collaoraon nodes are ncluded n he nal nformaon.. The selecon of vrual cluser heads (VCH). Monorng area s dvded no several clusers, accordng o he opmal proporon of cluser heads, communcaon area s dvded y S, supposed ha ρ CH s he proporon of cluser-heads (he rao of he numer of VCH requred and he oal numer of nodes), so he R round Cluser-Head selecon hreshold s shown n (). Fg.. Vrual MIMO cluser ransmng scheme. CH T = ρ, ρ *( rmod(/ ρ )) M CH CH () In order o faclae he research and dscusson, we make he followng assumpons:. Accordng o communcaon requremens, each sensor node may adop wo knds of communcaon mehods, namely and vrual MIMO, and he wo communcaon mehods can e convered each oher.. Vrual MIMO sysems adop Space-Tme Block Code (STBC), and he code s knd of Space- Tme Trells Code (STTC), s decodng s smple. 3. Supposed ha he nodes have compleed locaon and seleced her collaoraon nodes efore he neworks egn work, and each vrual MIMO ranscever consss of M neghor nodes. 4. Supposed ha he daa snk nodes have no any lmed n erms of energy and volume, and whch have mulple anennas, so can realze MIMO communcaon. 5. Supposed ha he poson of all nodes n he nework are equal, n he nal sae, all nodes have he same energy, he energy managemen sraegy adop dynamc power managemen, and has he aly of adapve adjusmen of ransmsson power. If he ransmsson power for oppose sde s oaned, he communcaon dsance of nodes can e calculaed accordng o he receved sgnal srengh ndcaor (RSSI). 6. Supposed ha all nodes deny no only s he only, u also have he aly o ge oher node ID. 7. Supposed ha communcaon s a a hgh sgnal-o-nose rao area, communcaons whn he cluser adop he aenuaon Gaussan whe nose (AGW) channel model, modulaon form adop wo phase shf keyng (BPSK). Communcaon eween clusers adop Raylegh fla fadng channel model, and modulaon form adop mul-and quadraure amplude modulaon (MQAM). where mod s he seekng modulo. Random numer ha s generaed y each node s eween 0 and. If T, hs node s chosen as he cluser head node, and send nformaon of cooperaon o s parners nodes o consue he VCH. 3. Cluser. VCH roadcas ID and AOCH (adversemen of cluser head) ha has ecome cluser head o all nodes n he regon. VMMS (vrual MIMO sensor nodes) are vrual MIMO ermnals excep VCH, whch judge he sgnal srengh of AOCH ha s roadcased y dfferen VCH, and send REG (regsraon) nformaon o he VCH ha have greaes sgnal srengh, hen, jon n her doman. 4. Tme-slo allocaon. TDMA slo s produced y VCH, whch s sen o s cluser memers, and each VMMS s assgned a me-slo. 5. Transmsson n cluser. Collaoraon nodes of VMMS exchange daa y he way of. The ransmed power s calculaed y dsance of collaoraon nodes, Accordng o he TDMA meslo allocaed y cluser head, n her own me gap, daa of M nodes are sen o VCH y vrual MIMO mode. Then VMMS reurn o he sleep sae o save energy unl he sep s acvaed agan. 6. Convergence. VCH ransm he daa of all he cluser nodes o S, hen, reurn o Sep, unl mos nodes of nework falure due o run ou of energy. 3. Energy Consumpon Analyss 3.. Energy Consumpon Model of ode The oal energy consumpon ha sen per daa y nodes, whch can e descred y () []: 70

4 Sensors & Transducers, Vol. 7, Issue 5, May 04, pp E ( α + ) PT + ( P + P ) T + P T on c de ecor on syn r =, () L where P, P, and P represen he energy consumpon of frequency synheszer, deecors and oher pars of he crcu respecvely. Ton = L/ R represens he me ha send L s of daa, and he -rae R = B, where s he numer of s ha ransmed per second per Hz andwdh and B s he modulaon andwdh. T r s he ransonal perod ha node conver from he sleepng mode o workng mode. α s rao ha deermned y he modulaon and. The ransmng power P can e expressed as a funcon of he communcaon dsance d and pah loss facor n []: (4 π ) P d n = E R d M (3) n (, ) GG rλ l f where G and G represen he anenna gan of r sendng ermnal and recevng ermnal respecvely. λ s he carrer wavelengh, M l s he lnk compensaon coeffcen of aenuaon, f s he recever nose fgure. E s per energy consumpon for he recevng ermnal n a ceran error rae, whose value s decded y he modulaon. For local communcaons, adops BPSK(mulple phase shf keyng) modulaon and = ; for MIMO communcaons, f adops BPSK modulaon, compared wh he, he energy effcency have no advanage, so adops MQAM (M-order quadraure amplude modulaon) modulaon and = [5]. Supposed ha Channel model s fla Raylegh fadng channel, he per energy consumpon of and MIMO have shown n (4) and (5) [0]: E M (4) P 0 / M MIMO P M ( ) (5) + M E M The energy consumpon for each under and MIMO ransmsson model s oaned y () - (5), has shown n (6) and (7) respecvely. M (4 π ) E d n = + M + 0 n (, ) ( α ) d / M P GG rλ f ( P + P ) R + c de ecor, sso P syn L T r (6) M MIMO P E ( d, n) = ( + α )( ) M M (4 π ) P n syntr d M ( f + Pc + Pde ecor ) R, mmo + GG rλ L (7) 3.. Calculaon of he ework Energy Consumpon In he prevous secon, sngle node energy consumpon n and MIMO modes s analyzed. On he ass of, he overall energy s consdered from sendng fxed daa vew pon. Supposed ha each node send L s daa, he energy consumpon of vrual MIMO and has shown n (8) and (9) respecvely. M M MIMO V MIMO k =, + k = = E ( Dd,, n) L E ( Dn, ) L E ( d, n) (8) E ( Dn, ) = LE ( Dn, ) (9) Before Vrual MIMO nodes send daa, hey need o complee he local communcaon whch dsance s d k, and exchange he nformaon of M collaorave nodes a he ransmng end. Therefore, for energy consumpon of vrual MIMO communcaon, we no only consder he energy consumpon n he long range communcaon, u also consder local communcaon energy consumpon eween collaoraon nodes. 4. Tme Delay Analyss and he Locaon Changes of Base Saon Influence on Energy Consumpon In wreless communcaon sysem whose energy s lmed, f he nework ransmsson delay s oo g, and he energy consumpon of sensor nodes wll e ncreased o some exen, hus he communcaon effcency of whole nework wll e affeced, especally n some specal occasons, he sysem delay requremens wll e hgher. For he nocooperave radonal ransmsson scheme whch has a fxed ransmsson andwdh B, he ransmsson delay s as follows: where T ra M = T s = (0) s he consellaon sze of he h node. s he ransmed symols of he h node. For he cooperave MIMO scheme, he oal delay consss of local communcaon delay of he 7

5 Sensors & Transducers, Vol. 7, Issue 5, May 04, pp sendng end and he recevng end and he longdsance ransmsson delay, and s as follows. T where MIMO M n = T ( + + ) M M r = s r s = m j= j and j () are he consellaon sze of he h h node n sendng end cluser and he j node n recevng end cluser for he local communcaon respecvely. The frs par and he hrd par are local communcaon delay sendng and recevng end respecvely, he second s he delay caused y longdsance MIMO ransmsson. The delay performance comparson char eween non-cooperave MIMO scheme and convenonal scheme has shown n Fg. 3. As can e seen from Fg. 3, when he ransmsson dsance s relavely smaller, he delay of MIMO s greaer han he convenonal scheme; and when he ransmsson dsance s [3,00], MIMO can effecvely reduce he delay and energy consumpon. consumpon was ncreased when he cluser head changed from 0m o 0m. Due o he ncreased dsance was reasonale communcaon range, so he resuls of Fg. 4 (a) and Fg. 4 () were smlar. Tale. The smulaon parameers. (a) Cluser-head dsance s 0 m Fg. 3. The delay performance comparson char eween non-cooperave MIMO scheme and convenonal scheme. In order o fully es he energy performance of he sysem under dfferen scenaros, hs paper analyzed he nfluence snk nodes poson changes on energy consumpon hrough smulaon. Supposed ha he 50 nodes were randomly dsrued n M M ( M = 00m ) square area, he ase saon (snk node) locaed regonal cener frsly, hen move along horzonal drecon o oserve he effec of dsance changes, smulaon parameers are shown n Tale. When he cluser head changes were 0m and 0m respecvely, he changes n energy consumpon have shown n Fg. 4. As can e seen from Fg. 4, When he dsance s shorer, he performance of s eer han ha of MIMO, however, when he dsance s relavely larger, compared wh, MIMO ( ) has a relavely lower energy consumpon, and MIMO ( ) s also lower han oher MIMO (3 3 and 4 4) energy. Fg. 4 has shown ha he oal energy () Cluser-head dsance s 0 m Fg. 4. The oal energy consumpon changes of Vrual MIMO and. The energy consumpon of and MIMO have shown n Fg. 5 when he communcaon dsance was longer, and n hs case, he energy consumpon of shor-dsance communcaon whn a cluser was no consdered, he communcaon performance of MIMO s eer han ha of whn he scope of he communcaon dsance. 7

6 Sensors & Transducers, Vol. 7, Issue 5, May 04, pp W = E (4), = (a) Cluser-head dsance s 0 m () Cluser-head dsance s 0 m Fg. 5. The energy consumpon of and MIMO n long dsance communcaon. 5. Analyss and Smulaon In he secon, he daa collecon process of a cluser s smulaed, Supposed ha communcaon area s a crcle whch radus s R, sensor nodes are dsrued y way of wo-dmensonal Posson n nework area, nodes densy s ρ,and he cluser head locae n he cener of crcle, each sensor node send L s daa o he cluser head. The communcaon dsance eween collaoraon nodes s he mean of d k, has shown n () []. E [ d k ] = d k = () 4 ρ On he ass of he precedng analyss, he oal energy consumpon of and MIMO has shown n (3) and (4) respecvely. W = E (3) V MIMO V MIMO, = In order o analyze he energy-savng rao W W MIMO (defned as ECR = ) of vrual MIMO W and, and n he case of n =.0 and he dfferen nodes dsruon densy, we compared W and WV MIMO, has shown n Fg. 6. Fg. 6 shown ha, compared wh, he vrual MIMO has hgher energy effcency n long ransmsson dsance, he energy-savng rao of vrual MIMO and s geng hgher wh R ncreasng when he node densy dsruon s no changed. Bu he node dsruon densy has nfluence on he energy effcency of vrual MIMO, When R remans consan, wh he ncrease of dsruon densy, he energy effcency of he vrual MIMO s ncreasng. When ρ = 0.00 and R > 40, compared wh, he energy effcency of vrual MIMO s more hgher, and when ρ = 0.05 and R >, compared wh, he energy effcency of vrual MIMO s more hgher. Ths s due o ake he energy consumpon of local communcaon no accoun n vrual MIMO, Therefore, he dsance eween he collaoraon nodes ncreases wh he reducon of node densy. Pah loss s an mporan facor for analyzng and desgnng of elecommuncaon sysems lnk udge. And s ofen affeced y propagaon envronmen, ransm meda, ransm dsance, anenna hegh and locaon and so on. n s used o represen pah loss ndex, whch usually changes from o 4. Propagaon model s under an deal free-space communcaon when n =, and s fla earh model when n = 4. In Fg. 6, pah loss facor s se o, Fg. 7 shown he relaonshp eween energy-savng rao and n. Energy consumpon of vrual MIMO and wll ncrease when he channel s no deal, However, wh he ncrease of n, he energy-savng rao s more hgher, and he energy effcency rao s more han 80 % when n > 3. I has shown ha vrual MIMO has eer energy-savng performance when pah loss s hgher Sysem Opmzaon Due o energy-consraned n WS, The numer of clusers s very key, f he numer of clusers s napproprae, he energy consumpon wll e ncreased, and leadng o rapd deah of WS. If he numer of clusers s oo lle, he numer of memers n a cluser wll ncrease, so he cluserheads ear oo heavy load, energy consumpon wll e acceleraed, and energy consumpon s malance. On he conrary, f cluser-heads are oo many, energy consumpon n formng clusers wll e 73

7 Sensors & Transducers, Vol. 7, Issue 5, May 04, pp ncreased, and nework lfeme wll e shorened. Therefore, he numer of clusers s very mporan wheher cluserng algorhm can realze low cos and relale daa ransmsson or no n gven condon. In order o alance energy consumpon of nodes, prolong nework lfeme, and mprove he relale daa ransmsson, he opmzaon prolem of he numer of cluser head s dscussed and analyzed. Supposed ha nodes densy s ρ, and hey are dsrued randomly n a M M square area whose edge s lengh s 00 m. The lfeme of nework s aken as he opmze arge, (he lfeme s defned as he perod ha s from he egnnng o half of nodes whch have ded) and ρ CH s searched eween % and 0 %. Calculaon codng adops nary encodng. The ndvdual numer n populaon s 0, he lengh of each populaon s 0, and he maxmum heredary generaon s 5. The ndvdual of nex generaon s chosen y he random raversal samplng whose generaon gap s 0.9. The reorganzaon s wo-pon crossover whose proaly s 0.7. The muaon proaly of each elemen n he chromosome s 0.5. Afer 5 mes of calculaon, he opmal soluon of ρ CH was oaned n several dfferen values of ρ, s shown n Fg. 8. Fg. 6. The relaonshp eween he vrual MIMO energy-savng raon and R. Fg. 8. The opmal soluon of ρ CH n several dfferen values of ρ Smulaon of VMMCA Scheme Fg. 7. The relaonshp eween he vrual MIMO.energy-savng rao and n In he opmzaon of sysem parameers, genec algorhm (GA) s an deal algorhm. Is prncple s ha use he effecve par of pas searched nformaon o do copyng, crossover and muaon on populaon whch a group of ndvdual formed, so GA has srong aly n he aspec of gloal search. In order o oan opmal rao of cluser head when he nework s lfeme s longes, cluser heads are calculaed and smulaed y GA oolox of Mala, he opmal value of ρ CH s oaned when VMMCA s operaed n dfferen dsruon densy of nodes. LEACH s a classc cluserng roung algorhm, whch can effecvely mprove he energy effcency of nework. On he ass of, cluser head s seleced randomly and cyclcally y LEACH, and vrual MIMO s appled o WS, a roung cluserng algorhm ased on vrual MIMO (VMMCA) s proposed. VMMCA can furher mprove energy effcency of nework, prolong he nework lfeme and mprove daa relale ransmsson. VMMCA s compared wh LEACH n he aspecs of he frs node deah round and nework lfeme and so on. Supposed ha sensor nodes are dsrued randomly n a M M square area whose edge s lengh s 00 m, and nodes densy ρ s 0.0, and hey have he same nal energy E 0, pah loss facor n s.0. Oher communcaon parameers are shown n Tale, he wo communcaon scheme are run under he dfferen values of ρ CH respecvely, hen he deah round of he frs node and he nework lfeme s oaned, s shown n Fg

8 Sensors & Transducers, Vol. 7, Issue 5, May 04, pp References Fg. 9. Comparave analyss of VMMCA and LEACH algorhm. ρ CH (%) As can e seen from Fg. 9, compared wh LEACH, VMMCA can sgnfcanly mprove he nework lfeme. The deah round of he frs node of VMMCA delay 4-6 mes han LEACH, and nework lfeme s aou -3 mes ha of he LEACH. 6. Conclusons The paper nroduced he vrual MIMO and dynamc power managemen echnology o WS, and pu forward a knd of energy-effcen VMMCA algorhm ha appled o small and medum-szed WS, and he algorhm are analyzed n he aspecs of desgn dea, desgn sraegy, desgn seps, ec. And hen energy alance and me delay of nework are analyzed, he energy consumpon of vrual MIMO and are analyzed n dfferen cluser sze, node dsruon densy, he pah loss ndex and changng of gaherng node, and he proporon of cluser heads s opmzed when he nework lfeme s longes y usng he genec algorhm under a ceran node dsruon densy. The smulaon resuls shown ha compared wh LEACH algorhm, VMMCA algorhm can prolong he nework lfeme, has he very good energy alance and relaly, and energy effcency of vrual MIMO nework s eer han ha of nework under he suale nework parameers. Acknowledgemens Ths work was suppored he Prory Academc Program Developmen of Jangsu Hgher Educaon Insuons (PAPD). []. Y. Song, R. Zhang, Z. Shen, e al., Analyss of energy consumpon of vrual MIMO wreless sensor nework, Journal of eworks, 7,, 0, pp []. L. L, Y. E. Zhang, M. H. Wang, e al., Communcaon Technology for Susanale Greenhouse Producon, Journal of Agrculural Machnery, 38,, 007, pp [3]. L. L. Zhou, Y. J. Hu, An adapve cooperave MIMO ransmsson scheme n WS, Journal of Anhu Unversy (aural Scences), 36,, 0, pp [4]. M. Xao, L. S. Huang, H. L. Xu, Vrual MIMO Mulcas-ased Mulhop Transmsson Scheme for Wreless Sensor eworks, Journal of Chnese Compuer Sysems, 33,, 0, pp [5]. S. K. Jayaweera, Vrual MIMO-ased cooperave communcaon for energy-consraned wreless sensor neworks, IEEE Trans. on Wreless Communcaons, 5, 5, 006, pp [6]. S. K. Jayaweera, M. L. Cheolu, R. K. Donapa, e al., Sgnal-processng-aded dsrued compresson n vrual MIMO-ased wreless sensor neworks, IEEE Trans. on Vehcular Technology, 56, 5, 007, pp [7]. Y. Zhang, Y. M. Ca, X. M. Chen, e al., A novel cooperave MIMO-ased ransmsson scheme for wreless sensor neworks, Chnese Hgh Technology Leers, 8,, 008, pp [8]. Y. Zou, Q. Gao, F. L, e al., Energy opmzaon of wreless sensor neworks hrough cooperave mmo wh daa aggregaon, Personal ndoor and mole rado communcaons, n Proceedngs of he IEEE s Inernaonal Symposum, 00, pp [9]. V. Mahnhan, C. Ln, Parner selecon ased on opmal power allocaon n cooperave-dversy sysems, IEEE Transaconson Vehcular Technology, 57,, 008, pp [0]. Shuguang Cu, Goldsmh A J, Baha A., Energyeffcency of MIMO and cooperave MIMO echnques n sensor neworks, IEEE Journal on Seleced Areas n Communcaons,, 6, 004, pp []. Bravos G, Kanaas A G., Energy effcency comparson of MIMO-ased and mulhop sensor neworks, EURASIP Journal on Wreless Communcaons and eworkng, 008, 008, []. Proaks J G. Dgal Communcaons, 4 h ed., McGrawHll, ew York, 000, pp [3]. Y. Song, J. Ma, Y. Feng, Desgn and Analyss of Vrual MIMO-Based Low-Power Conrol Algorhm for WS, Research Journal of Appled Scences, Engneerng and Technology, 5, 7, 03, pp Copyrgh, Inernaonal Frequency Sensor Assocaon (IFSA) Pulshng, S. L. All rghs reserved. (hp:// 75