Nekuvandudzwa kwematanho ekutaurirana akananga kubroadband uye kufamba, iyo optical fiber isina waya yekutaurirana system (ROF) inobatanidza optical fiber kutaurirana uye kutaurirana pasina waya, ichipa kutamba kwakazara kune zvakanakira Broadband uye anti-kupindira kweOptical fiber mitsara, pamwe nekutaurirana pasina waya. . Zviri nyore uye zvinochinjika zvinosangana nezvinodiwa nevanhu zvebroadband. Iyo yekutanga ROF tekinoroji yaive yakatsaurirwa kupa yakakwira-frequency isina waya yekufambisa masevhisi, senge millimeter wave optical fiber transmission. Nekuvandudzwa uye kukura kweROF tekinoroji, vanhu vakatanga kudzidza hybrid wired uye wireless transmission network, kureva, optical fiber wireless communication (ROF) masisitimu anopa waya uye mawaya masevhisi panguva imwe chete. Nekukurumidza kusimukira kwekufambiswa kwemashoko neredhiyo, kushaikwa kwezviwanikwa zvema spectrum kwawedzera uye kwakakurumbira. Maitiro ekuvandudza mashandisirwo emagetsi pasi pemamiriro ezvishoma zviwanikwa zvisina waya kudzikamisa kupokana pakati pekupa uye kudiwa kweiyo spectrum zviwanikwa rave dambudziko rinogadziriswa mumunda wekutaurirana. Cognitive radio (CR) inyanzvi yekugovana tekinoroji. Inogona kunyatso kuvandudza mashandisirwo ezviwanikwa kuburikidza ne "secondary kushandiswa" kweane mvumo spectrum, uye yave hotspot yekutsvagisa mundima yekutaurirana. Mu802.11 isina waya yenzvimbo yenzvimbo network [1], 802.16 metropolitan area network [2] uye 3G mobile communication network [3] vatanga kudzidza mashandisirwo eruzivo rweredhiyo tekinoroji kuvandudza kugona kwehurongwa, uye vakatanga kudzidza mashandisiro ekushandisa. ROF tekinoroji yekuwana yakasanganiswa kutapurirana kweakasiyana masaini masaini[4]. Cognitive redhiyo-yakavakirwa optical fiber isina waya yekutaurirana network inotumira waya uye isina waya masaini ndiyo nzira yekuvandudza yeramangwana rekukurukurirana network. Iyo hybrid transmission ROF system yakavakirwa pakuziva redhiyo tekinoroji inotarisana nematambudziko mazhinji matsva, senge network yedhizaini dhizaini, layer protocol dhizaini, chizvarwa chewaya uye isina waya modulated masiginecha zvichibva pamasevhisi akawanda, manejimendi manejimendi, uye kuzivikanwa kwemasaini akagadziridzwa.
1 Cognitive radio tekinoroji
Cognitive redhiyo inzira inoshanda yekugadzirisa kushomeka kweiyo spectrum uye kusashandiswa kwe spectrum. Cognitive redhiyo inyanzvi isina waya yekutaurirana system. Inonzwa mashandisirwo emhando yenzvimbo yakatenderedza uye inogadzirisa maparamita ayo ega ega kuburikidza nekudzidza kuti iwane kushandiswa kunoshanda. Spectrum zviwanikwa uye kutaurirana kwakavimbika. Iko kushandiswa kweredhiyo yekuziva ndiyo yakakosha tekinoroji yekuona iyo spectrum sosi kubva pakugovaniswa kwakagadziriswa kuenda kune ine simba kugoverwa. Muchirongwa cheredhiyo chekuziva, kuitira kuchengetedza mushandisi ane mvumo (kana kuve shasha mushandisi) kubva mukukanganiswa kubva kumushandisi wenhapwa (kana CR mushandisi), basa rekuona spectrum kuona kana mushandisi ane mvumo aripo. Cognitive radio vashandisi vanogona kushandisa kwenguva bhendi frequency kana ichiongororwa kuti frequency bhendi inoshandiswa nemushandisi ane mvumo haisi kushandiswa. Kana ikatariswa kuti frequency bhendi yemushandisi ane mvumo iri kushandiswa, mushandisi weCR anoburitsa chiteshi kumushandisi ane mvumo, nekudaro ave nechokwadi chekuti mushandisi weCR haapindire nemushandisi ane mvumo. Naizvozvo, iyo yekuziva isina waya yekutaurirana network ine zvinotevera zvinoyemurika maficha: (1) Mushandisi wekutanga anokoshesa zvakakwana kuwana chiteshi. Kune rimwe divi, kana mushandisi ane mvumo asingatore chiteshi, mushandisi wechipiri ane mukana wekuwana iyo isina basa chiteshi; kana mushandisi wekutanga abudazve, mushandisi wechipiri anofanira kubuda mugero mukushandiswa nenguva uye odzosera chiteshi kumushandisi wekutanga. Kune rimwe divi, kana tenzi mushandisi akabata chiteshi, mushandisi wenhapwa anogona kuwana chiteshi pasina kukanganisa kunaka kwesevhisi yemushandisi. (2) Iyo CR yekutaurirana terminal ine mabasa ekuona, manejimendi uye kugadzirisa. Kutanga, iyo CR yekutaurirana terminal inogona kuona iyo frequency spectrum uye chiteshi nharaunda munzvimbo yekushanda, uye kuona kugovana uye kugoverwa kweiyo spectrum zviwanikwa zvinoenderana nemimwe mitemo zvinoenderana nemhedzisiro yekuona; kune rumwe rutivi, CR communication terminal ine simba rekugadzirisa maitiro ekushanda pamhepo, zvakadai sekuchinja Maitiro ekutumira akadai semutakuri frequency uye modulation nzira inogona kuenderana nekuchinja kwezvakatipoteredza. Mune cognitive wireless communication network, spectrum sensing ndiyo yakakosha tekinoroji. Inowanzo shandiswa spectrum sensing algorithms inosanganisira kuona simba, inofananidzwa nesefa yekuona, uye cyclostationary maitiro ekuona nzira. Nzira idzi dzine zvadzakanakira nezvadzinoipira. Kuita kwema algorithms aya kunoenderana neruzivo rwekutanga rwakawanikwa. Iyo iripo spectrum sensing algorithms ndeiyi: inofananidzwa sefa, simba rekuona uye maitiro e detector maitiro. Iyo inofananidzwa sefa inogona kushandiswa chete kana chiratidzo chikuru chazivikanwa. Iyo detector yemagetsi inogona kushandiswa kumamiriro ezvinhu apo chiratidzo chikuru hachizivikanwi, asi kushanda kwayo kunokanganisa kana nguva pfupi yekunzwa inoshandiswa. Nekuti iyo pfungwa huru yechinhu detector ndeye kushandisa cyclostationarity yechiratidzo kuona kuburikidza neiyo spectral correlation basa. Ruzha chiratidzo chakamira chakafara uye hachina hukama, nepo modulated chiratidzo chakabatana uye cyclostationary. Naizvozvo, iyo spectral correlation basa inogona kusiyanisa simba reruzha uye simba reiyo modulated chiratidzo. Munzvimbo ine ruzha rusina chokwadi, kushanda kweiyo detector yemhando iri nani pane iyo yemagetsi detector. Kuita kwechinhu che detector pasi peyero yakaderera-kune-ruzha reshiyo ishoma, ine yakakwira computational kuomarara, uye inoda nguva yakareba yekutarisa. Izvi zvinoderedza data throughput yeCR system. Nekuvandudzwa kwewireless communication technology, spectrum zviwanikwa zviri kuramba zvichiwedzera kunetsa. Nekuti CR tekinoroji inogona kuderedza dambudziko iri, CR tekinoroji yakatariswa kune isina waya yekutaurirana network, uye mazhinji asina waya yekutaurirana network miyero yakaunza cognitive radio tekinoroji. Zvakadai seIEEE 802.11, IEEE 802.22 uye IEEE 802.16h. Muchibvumirano che 802.16h, pane zvakakosha zvemukati zvekusarudzwa kwe dynamic spectrum kufambisa kushandiswa kweWiMAX kweredhiyo neterevhizheni frequency band, uye hwaro hwayo ihunyanzvi hwekunzwa tekinoroji. MuIEEE 802.11h chiyero chepasi rose cheasina waya yenzvimbo network, pfungwa mbiri dzakakosha dzakaunzwa: dynamic spectrum selection (DFS) uye transmit power control (TPC), uye redhiyo yekuziva yakaiswa kune isina waya yenzvimbo network. Mune 802.11y chiyero, orthogonal frequency division multiplexing (OFDM) tekinoroji inoshandiswa kupa dzakasiyana siyana bandwidth sarudzo, iyo inogona kuwana nekukurumidza bandwidth switch. WLAN (wireless local area network) masisitimu anogona kutora mukana wehunhu hweOFDM kudzivirira kudzivirirwa nekugadzirisa bandwidth uye kutumira magetsi ma paramita. Kukanganisa nevamwe vashandisi vanoshanda mune ino frequency band. Nekuti iyo optical fiber isina waya system ine mabhenefiti ehupamhi optical fiber kutaurirana bandwidth uye inochinjika hunhu hwekutaurirana isina waya, yakashandiswa zvakanyanya. Mumakore achangopfuura, kutapurirana kweredhiyo frequency cognitive WLAN masiginecha mune optical fiber kwakakwezva kutarisa. Munyori wezvinyorwa [5-6] akakurudzira kuti ROF system Kuziva masaini eredhiyo anofambiswa pasi pezvivakwa, uye kuenzanisa kuyedza kunoratidza kuti network kuita kwakagadziridzwa.
2 ROF-yakavakirwa hybrid optical fiber isina waya yekufambisa sisitimu yekuvaka
Kuti usangane nezvinodiwa zvemultimedia masevhisi ekufambisa kwevhidhiyo, iyo inosimuka fiber-kune-imba (FFTH) ichave yekupedzisira Broadband yekuwana tekinoroji, uye iyo passive optical network (PON) yave yekutarisisa kana yangouya. kunze. Sezvo zvigadziriso zvinoshandiswa muPON network zviri zvigadziriso, hazvidi magetsi, zvinogona kudzivirirwa kusimba rekukanganiswa kwemagetsi ekunze uye mheni, zvinogona kuwana pachena kutapurirana kwemasevhisi, uye kuve nekuvimbika kwehurongwa hwepamusoro. PON network inonyanya kusanganisira nguva yekuparadzanisa multiplexing passive optical network (TDM-PON) uye wavelength division multiplexing passive optical network (WDM-PON). Kuenzaniswa neTDM-PON, WDM-PON ine hunhu hwemushandisi wega bandwidth uye kuchengetedzwa kwepamusoro, ichiva yakanyanya kugona yekuona network mune ramangwana. Mufananidzo 1 unoratidza iyo block diagram yeWDM-PON system.