OFDM ua fa'atū mai ile IEEE802.11a. Faʻavae i luga o lenei metotia o le faʻaogaina, e tatau ona tatou iloa le mea ole OFDM e malamalama ai i tulafono eseese.
O le a le OFDM?
O le OFDM o se faʻapitoa faʻapipiʻi faʻaogaina tekonolosi. O lenei tekinolosi e fa'amoemoe e vaevae se alalaupapa i ni nai laina pito i lalo, ona fa'aliliuina lea o fa'amaumauga o fa'amatalaga maualuga-maualalo i lalo o fa'amaumauga maualalo mo fa'asalalauga tutusa, lea e fa'aogaina ma tu'uina atu i so'o ta'itasi. O subcarrier ta'itasi e fa'atasi i le isi, ma o ala o alaleo pe a mae'a fa'asalalau alaleo e mafai ona felavasa'i, fa'aitiitia ai le fa'alavelave i le va o subcarriers ma fa'aleleia le fa'aogaina o alaleo.
E faʻafefea ona malamalama i le orthogonal leai se faʻalavelave: pe a oʻo le tasi subcarrier i le pito i luga, o le amplitude o le isi subcarrier o le 0. O lona uiga, o le lua subcarriers o le orthogonal e aunoa ma le faʻalavelave. E pei ona faʻaalia i le ata o loʻo i lalo, pe a maualuga le maualuga o le taunuu mai lanumoana, o le isi subcarrier e 0.
E le gata i lea, e mafai e le OFDM ona faʻaogaina subcarriers e faʻafefe ona o subcarriers ua faʻamalamalamaina i se auala e faigofie ai ona taʻu eseese.
Ua vaevaeina le faailo i ni subcarriers se tolu, mai le agavale i le taumatau. O pito pito i lalo ta'itasi e fa'aogaina mo fa'amatalaga fa'amaumauga, e pei ona fa'aalia i le togi mumu i le ata, lea e fetaui ma le 0 fua laina i lalo. O le tasi e oʻo i le tumutumu, ae o le isi e oʻo atu i le 0. O nei subcarriers ua fuafuaina ma le loto i ai e faʻatumauina se sootaga faʻatasi ma le tasi. Le tumutumu o subcarrier taitasi I le taimi nei, o le amplitude o isi subcarrier e lua e 0.
5GHz OFDM alavai:
O le alalaupapa 5GHz e 52 subcarriers, ma o subcarrier taitasi e 312.5 kHz. E 48 alalaupapa mo le fa'asalalauina o fa'amaumauga, ma 4 alalaupapa e fa'aaogaina mo fa'amatalaga vaega.
O le OFDM subchannel modulation technology e faʻaogaina ai le QAM (QAM o le faʻapuupuuga o le quadrature amplitude modulation, lea e faʻaliliuina o le "quadrature amplitude modulation" i le gagana Saina). QAM fa'aogaina le amplitude ma le vaega o le galu ave e fa'asalalau fa'amatalaga.
O loʻo i luga o le faʻamatalaga malamalama o le OFDM-802.11 protocol na aumai ia te oe eShenzhen HDV Phoelectron Technology Co., Ltd. fa'amoemoe e mafai e lenei tusiga ona fesoasoani ia te oe e fa'ateleina lou malamalama. E ese mai i lenei tusiga pe afai o loʻo e suʻeina se kamupani gaosi mea tau fesoʻotaʻiga fiber optical e mafai ona e mafaufau i aifaatatau ia tatou.
O oloa tau feso'ota'iga na gaosia e le kamupani e aofia ai:
Module: fa'apipi'i alava mata, Ethernet modules, opitika fiber transceiver modules, fa'aoga fa'aoga alava mata, SSFP fa'aogaina mata'itusi, maSFP alava mata, ma isi.
ONUvaega: EPON ONU, AC ONU, alava mata ONU, CATV ONU, GPON ONU, XPON ONU, ma isi.
OLTvasega: OLT sui, GPON OLT, EPON OLT, fesootaigaOLT, ma isi.
O oloa o lo'o i luga e mafai ona lagolagoina fa'aaliga feso'otaiga eseese. Mo oloa o loʻo i luga, o loʻo tuʻufaʻatasia se 'au R & D faʻapolofesa ma malosi e tuʻuina atu le lagolago faʻapitoa mo tagata faʻatau, ma e mafai e se au pisinisi mafaufau ma faʻapolofesa ona tuʻuina atu auaunaga maualuga mo tagata faʻatau vave.feutagaigama galue mulimuli ane.