Ua noi ʻia ʻo OFDM ma IEEE802.11a.Ma muli o kēia ʻano o ka modulation, pono mākou e ʻike i ke ʻano o OFDM e hoʻomaopopo i nā protocols like ʻole.
He aha ka OFDM?
ʻO OFDM kahi ʻenehana modulation multi-carrier kūikawā.Ke manaʻo nei kēia ʻenehana e hoʻokaʻawale i kahi ala i loko o kekahi mau sub-channels orthogonal, a laila hoʻohuli i nā hōʻailona ʻikepili kiʻekiʻe i nā kahawai sub-data haʻahaʻa no ka hoʻoili like ʻana, i hoʻololi ʻia a hoʻouna ʻia ma kēlā me kēia sub-channel.He orthogonal kēlā me kēia subcarrier i kekahi, a ʻo nā ala alapine ma hope o ka hoʻolaha ʻana o ka spectrum modulation hiki ke uhi ʻia, e hōʻemi ana i ka interference ma waena o nā subcarriers a me ka hoʻomaikaʻi ʻana i ka hoʻohana ʻana i ka spectrum.
Pehea e hoʻomaopopo ai i ka orthogonal no interference: i ka hiki ʻana o kekahi subcarrier i ka piko, ʻo ka amplitude o ka subcarrier ʻē aʻe he 0. ʻO ia hoʻi, ʻo nā subcarrier ʻelua he orthogonal me ka ʻole o ke keakea.E like me ka mea i hōʻike ʻia ma ke kiʻi ma lalo nei, ke kiʻekiʻe loa ka amplitude hōʻea polū, ʻo ka subcarrier ʻē aʻe he 0.
Eia kekahi, hiki i ka OFDM ke hoʻohana i nā subcarriers e overlap no ka mea ua wehewehe ʻia nā subcarriers i kahi ala e maʻalahi ai lākou e wehewehe.
Ua māhele ʻia ka hōʻailona i ʻekolu subcarrier, mai ka hema a i ka ʻākau.Hoʻohana ʻia kēlā me kēia kiʻekiʻe subcarrier no ka hoʻopili ʻana i ka ʻikepili, e like me ka hōʻike ʻana ma ke kiko ʻulaʻula ma ke kiʻi, e pili ana i ka laina unahi 0 ma lalo.Hiki i kekahi i ka piko, a ʻo ke koena a hiki i ka 0. Ua hoʻolālā ʻia kēia mau subcarriers e mālama i kahi pilina orthogonal me kekahi.ʻO ka piko o kēlā me kēia subcarrier I kēia manawa, ʻo ka amplitude o nā subcarrier ʻelua ʻelua he 0.
5GHz OFDM channel:
He 52 mau subcarrier ka 5GHz, a he 312.5 kHz kēlā me kēia subcarrier.Aia he 48 mau ala no ka hoʻouna ʻana i ka ʻikepili, a hoʻohana ʻia nā kaha 4 no ka kuhikuhi ʻana i ka pae.
Hoʻohana ka ʻenehana subchannel modulation OFDM i ka QAM (ʻo QAM ka pōkole o ka quadrature amplitude modulation, i unuhi ʻia ʻo "quadrature amplitude modulation" ma ka ʻōlelo Kina).Hoʻohana ʻo QAM i ka amplitude a me ka pae o ka hawewe lawe e hoʻouna i ka ʻike.
ʻO ka mea ma luna nei ka wehewehe ʻike o ka protocol OFDM-802.11 i lawe ʻia iā ʻoe eShenzhen HDV Phoelectron Technology Co., Ltd.manaʻolana hiki i kēia ʻatikala ke kōkua iā ʻoe e hoʻonui i kou ʻike.Ma waho aʻe o kēia ʻatikala inā ʻoe e ʻimi nei i kahi ʻoihana mea hana uila fiber optical maikaʻi āu e noʻonoʻo aie pili ana iā mākou.
ʻO nā huahana kamaʻilio i hana ʻia e ka hui e uhi:
Module: nā modules fiber optical, Nā modules Ethernet, nā modules transceiver fiber optical, nā modules komo fiber optical, SSFP mau modula optical, aʻO nā fiber optical SFP, etc.
Māhele ONU: EPON ONU, AC ONU, puluniu maka ONU, CATV ONU, GPON ONU, XPON ONU, etc.
Papa OLT: hoʻololi OLT, GPON OLT, EPON OLT, kamaʻilio OLT, etc.
Hiki i nā huahana ma luna ke kākoʻo i nā hiʻohiʻona pūnaewele like ʻole.No nā huahana i luna, ua hui pū ʻia kahi hui R&D ʻoihana a ikaika e hāʻawi i ke kākoʻo ʻenehana no nā mea kūʻai aku, a hiki i kahi hui ʻoihana noʻonoʻo a ʻoihana ke hāʻawi i nā lawelawe kiʻekiʻe no ka poʻe kūʻai mua.kūkākūkāa ma hope o ka hana.