Tiết kiệm năng lượng trong mạng cảm biến vô tuyến

Tran Manh Dat<br /> <br /> TONG QUAN MOT V A I DAC TRl/NG CUA MANG WSN<br /> Mang cam bien vd rayen (WSN - Wueless Sensor Mpt node trong mang WSN thdng thudng bao gdm<br /> Network) ed thi Meu don giin Id mang Uen kit cac 2 phan: Phan cam bien (sensor) hoac dllu kMen vd<br /> node vdi nhau bdng kit ndi sdng vd tuyin trong phan giao tiep vd tayen. Do sd luong node trong<br /> dd cae node mang thuang la eae tMet hi don gian, WSN la ldn vd khdng can cdc hopt dpng bao tri, nen<br /> nhd gpn, gid thdnh thap... va co sd lupng ldn, dupe yeu cau thdng thudng ddi vdi 1 node mpng Id gid<br /> phan bd mpt each khdng cd cau tnic cu the (non- thdnh thap vd kich thudc nhd gpn.<br /> topology) sit dung ngudn nang lupng han ehe (pin),<br /> Do gidi hpn ve ngudn ndng luong cung cap (pin...),<br /> cd thdi gian hoat dpng lau dai (vdi thdng den vai<br /> gia thdrih va yeu cau hopt dpng trong mpt thdi gian<br /> nam) vd cd the hoat ddng trong mdi tradng khde<br /> ddi, nen van de tieu thu nang lupng Id tieu chi thiet<br /> ngMet (chat ddc, d nMlm, nMet dp...).<br /> ke quan trpng nhat trong mpng cam biin:<br /> Cae node mpng thudng ed chire ndng cam bien<br /> - WSN thudng dupe trien khai tren mdt phpm vi<br /> (sensor node): Cam img, quan sat mdi tradng xung<br /> rpng, sd lupng<br /> quanh (nhu nMet dp, dp am, anh sang)... theo doi<br /> node mang ldn<br /> hay dinh vi cae muc tieu ed dinh hodc di dpng... Cac<br /> vd dupe phdn<br /> node giao tiep ad-hoc voi nhau vd trayen dii Ueu vl<br /> bd mdt each<br /> trang tam mpt each gian tiep.<br /> taong ddi nglu<br /> Luu lupng dii Ueu luu thong trong WSN Id thap va nMen, eac<br /> khdng Uen tiic do vay de tiet kiem nang lupng, eae node mpng ed<br /> node cam bien thudng ed nMlu ehl dp hoat ddng the di chuyen<br /> vd che dp ngM khac nhau. Thdng thudng thai gian ldm thay ddi<br /> 1 node d trang thai ngM Ion hon a trang thai hoat so dd mang.<br /> dpng rat nMeu.<br /> <br /> <br /> <br /> 34 TAP CHI CNTT&TT KY 1 (6.2010)<br />  CONG NGHE VIEN THONG<br /> <br /> <br /> Semantic Peer-to-Peer<br /> Communication<br /> <br /> * " . /<br /> <br /> <br /> <br /> <br /> Mobile Ad-lioc Networks<br /> <br /> <br /> Mgng WSN<br /> Hinh 1: Phan biet mang WSN vol mang ad-hoc<br /> <br /> do vdy WSN ddi hdi mdt cau Mnh mpng (topology) CAC QNG DUNG CUA MANG W S N<br /> Unh dpng (ad-hoc, mesh, star...) va cac node mang WSN duoc img dung dau tien trong cae linh<br /> cd kha ndng tu dieu chinh, tu cau Mnh (auto- vuc qudn su. Ciing vdi su phat trien ciia ngdnh<br /> reeonfigurable). cdng nghiep dieu kMen tu ddng, robotic, tMit bi<br /> - Trong mpt sd WSN thdng dung, dia cM ID eac thdng mmh, mdi traong, y tl... WSN ngdy edng<br /> node chinh Id vi tri dia ly vd giai thuat dinh tayen dupe sit dung nMeu trong hopt ddng edng nhiep<br /> dua vdo vi tri dia ly ndy gpi Id giao thitc dinh tayen vd ddn dung. Mpt sd img dung eo ban eua WSN:<br /> theo vi tri dia ly GRT (Geography Routing Protocol).<br /> Do gidi han kha nang tinh todn cua timg node - Cam bien mdi tradng (qudn su: Phat Men min,<br /> mpng ciing nhu de tilt kiem nang lupng, WSN chat ddc, dich chuyen quan dieh...; cdng ngMep:<br /> thudng sit dung cdc phuang phdp tinh toan va xit He thdng cMeu sang, dp am, phdng chay, chdng rd<br /> ly tin Meu phi tap trang de giam tai cho node gan ri...; dan dung: He thdng dieu hda nMet dp, chiiu<br /> hit ndng lupng hodc gui dii Ueu can tinh todn cho sang...)<br /> cae trpm gdc. - Dieu khien (quan su: Kich hoat tMet bi, vu khi<br /> qudn su...; cdng ngMep: Dieu kMen tu dpng eac<br /> tMet bi, robot...)<br /> PHAN BIET WSN V O I MANG AD-HOC<br /> - Theo ddi, gidm sdt, dinh vi (qudn su: Dinh vl,<br /> Mang tuy biin ad-hoc la mang trong dd cac node<br /> theo ddi su dich chuyen tMet hi, quan dpi...)<br /> kit ndi vdi nhau theo chl dp ad-hoe ngMa la khdng<br /> ed ha tang mang, dinh Myen thay ddi ldn... Vi du - Mdi tradng (0am sat lii lut, bao, gid, mua... phat<br /> don gian la nMeu laptop, mdy di ddng kit ndi vdi Men d nhilm, chat thai...<br /> nhau chinh Id mpt mpng ad-hoc.<br /> Mang WSN la mang ad-hoc dupe tpo nen ta cae<br /> bp cam bien. WSN khac ad-hoc d chd WSN tinh di<br /> dpng thap vl chiing thudng dupc ddt cd dinh. Su<br /> phan biet giira hai mpng ndy dupe the Men true<br /> quan trong Hinh 1.<br /> <br /> <br /> <br /> <br /> TAP CHI CNTT&TT KY 1 (6.2010) 35<br />  CONG NGHE VIEN THONG<br /> <br /> <br /> vdi muc dieh giam ndng lupng tieu thu.<br /> - Tilt kiem ndng luong ttong cdc giao thirc diiifi<br /> tayin: Trong mang adhoc ndi chung, vd WSN ndi<br /> rieng, dudng di giira cac node trong mpng se thay<br /> ddi theo thdi gian (do node di chuyen, do chat lupng<br /> kenh trayen thay ddi theo thdi tilt, do node hit<br /> ndng luong). Tilt kiem ndng Id mpt van de phire tpp-<br /> Mdt sd bdi todn dupe dat ra nhu: Ldm thi ndo de<br /> xdy dung dupe thuat toan dinh rayen nhanh chdng<br /> ma khdng can phai giii tdi tat ea cae node trong<br /> mang. Can mdt thuat todn tlm dudng di md sao cho<br /> - Y te (dinh vi, theo ddi berih nhdn, he thdng bdo<br /> tdng ndng luong tieu tdn Id thap nhat hoac ti le giiia<br /> dpng khan cap...)<br /> lupng dii Ueu trayen vd ndng lupng tieu thu Id cao<br /> - He thdng giao thdng thdng minh: Giao tiip giira<br /> nhat...<br /> hiln bao vd phuong tien giao thdng, he thdng dieu<br /> tilt luu thdng cdng epng, he thdng bao Meu tai npn, - Tilt kiem ndng lupng trong quin ly bao mat:<br /> ket xe... he thdng dinh vi phuong, trp giiip dllu Sii dung mdt eo che phan bd, cung cap vd quan ly<br /> kMen tu ddng phuang tien tien giao thdng... khda bao mat kM mpt node ta bd khdi mpng WSN,<br /> hoae mot nhdm nhiing node trong mang bit diu<br /> - Gia dlrih (rihd thdng muih: He thdng cam biin,<br /> trao ddi vdi nhau sao cho sd luong ban tui trao ddi<br /> giao tiep vd dieu kMen cae tMet hi thdng minh...)<br /> giiia eac node Id thap nhat, qua dd tilt kiem ndng<br /> Ndi ehung, mpng WSN tao ra mdi tradng giao lupng tieu thu.<br /> tiep giira cdc tMet bi thdng minh, giira cdc thilt bi<br /> Ngodi ra thdng tin edn the duoc xit ly trade<br /> thdng minh vd con ngudi vd giao tiep giiia cac tMet<br /> kM giii di dl giam nang luong tieu thu chung.<br /> bi thdng minh vd cae he thdng viin thdng khdc.<br /> <br /> KET LUAN<br /> NANG LU'ONG TRONG MANG WSN<br /> Tilt kiem nang lupng trong hau hit cdc mpng/<br /> Ndng lupng, khdng cM trong mpng WSN md ngdy tMet bi vien thdng dang Id mdt van de dupe quan<br /> nay van de ndy edng dupc quan tdm trong tat ca ede tdm hang dau ddi vdi cac nhd mpng eiing nhu ngudi<br /> edng nghe di dpng khac, nhdm tdng thdi gian sdng sii dung. Tuy nMen, vdi ddc tirih rieng eiia minh, vai<br /> cua ede tMit bi. Rieng ve mang WSN, ndng lupng ttd cua tilt kiem nang lupng trong mpng WSN Id cue<br /> Id mpt van de quan trong cap tMet. Lam the nao de ky quan trpng. Nd anh hudng true tiip din thdi gian<br /> giam tMeu ndng lupng bdng "phan mem"? De ldm sdng eiia eac bp cam blln trong, qua dd Inh hudng<br /> dupc dieu dd, tat ca cdc giao thire trayin thdng phai den Meu qua eua todn he thdng. Tuy nMen, neu dp<br /> huong din tilt kiem ndng lupng. dung tdt cdc cdng nghe mdi phii hpp tM chinh WSN<br /> - Tilt kiem ndng lupng d ldp vdt ly: Sit dung ky lpi la mang ed nMlu nMeu tilm ndng trong viec tilt<br /> thuat dieu ehe tin Meu sd: 0-QPSK, FSK cat tMen kiem ndng lupng.<br /> Meu suit bd khuich dpi cdng suat. Cdc ky thuat ma<br /> hda siia sai phite tap nhu Turbo Code, LDPC khdng<br /> Tai lieu tham khao<br /> dupc sit dung, ky thuat trai phd dupc su dung de ell<br /> tMen SNR d tMet bi thu vd giam tac dpng eua fading [ 11. ANNA HAC, Wireless Sensor Network Deigns.<br /> <br /> kerih trayen... [21. EDGAR H. CALIAWAY JR, Wireless Sensor Network^:<br /> <br /> - Tilt kiem ndng luong d Idp MAC: Sit dung ky Architectures and Protocols, Auerbach Publications 2004.<br /> <br /> thuat da tray cap TDMA hoae CSMA-CA Meu ehinh 131. http://vntelecom.org/<br /> <br /> <br /> <br /> 36 TAP CHI CNTT&TT KY 1 (6.2010)<br />