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WiFi講座(3)
(Japanese document)
Wi-Fi history, spec, background of data signaling rate, and so on
社内ゼミでの資料です。
urakarin
May 02, 2017
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Wi-Fi ͕͘͠ײ͡Δཧ༝ • ແઢ͔ͩΒʹݟ͑ͳ͍ɻΤϥʔ͔ͯ͠Βͳ͍ɻ • ༷͕ͦͦݐ૿͠Ͱ૿͑͗͢ɻ৽ͬ͞ΆΖӺঢ়ଶɻ • ͱͱͷ༷ʹOption߲͕ଟ͍ɻ • ͦͷͨΊɺઃఆ߲͕ଟ͍ɻ
• ֤ϝʔΧΑ͔Εͱࢥͬͯɺػೳʹ͔Γ͍͢ѪশΛ͚ͭΔͨΊ༨ܭࠞཚ͢Δɻ • 802.11ن֨ͱWi-Fi Allianceن֨ͱಠࣗن͕֨ࠞࡏɻ • ಠࣗن֨ɺࣅ͍ͯͯඍົʹҧ͏ػೳʹͦΕͧΕҧ͏໊લ͕͋Δɻ • ԣจࣈ͕ଟ͍ɻಛʹ3-4จࣈͷӳࣈུޠ͕ଟ͍ɻ • ٕज़ʹର͢ΔΓޱ͕ଟ͍ɻ • ֶతʹ͍͠ʢมௐɺ҉߸ͳͲʣ -
Wi-Fi ͱʁ IEEE802.11ʹن֨ͷᐆດ͕͋ͬͨ͞Γɺଓࢼݧํ͕ࣜͳ͍͜ͱ͔Βɺ ૬ޓଓೝূϓϩάϥϜΛઃ͚ͨۀքஂମɻϩΰΛఏڙ͢Δɻ IEEEͷن֨Խʹ͕͔͔࣌ؒΔ߹ͳͲɺ Wi-Fi Allianceͱͯ͠ೝূϓϩάϥϜΛ։࢝ ͢Δ͜ͱ͋Δɻ Wi-Fi Alliance
ͷ͜ͱɻ http://www.wi-fi.org/ IEEE ͱʁ ? ( Wi-Fi = Wireless Fidelity ) -
IEEE ͱʁ ͦΕͧΕͷඪ४͝ͱʹɺಠཱͨ͠Պձ͕ଘࡏ͍ͯ͠Δɻ ʮిؾֶɾిࢠֶٕज़ͷֶձʯ ͷ͜ͱɻ The Institute of Electrical and
Electronics Engineers, Inc. ྫʣ• IEEE 488 : GPI-IB • IEEE 802 : LAN, MAN, PAN • IEEE 1003 : POSIX • IEEE 1394 : FireWire (i.Link) • 802.1 : LANٴͼMANͷجຊతͳ༻ • 802.3 : Ethernet • 802.5 : τʔΫϯϦϯά • 802.11 : WLAN (Wi-Fi) • 802.15 : WPAN • 802.15.1 : (Bluetooth) • 802.15.4 : • (ZigBee) • (Wi-SUN) WGͷྫʣ -
802.11ͷྺ࢙ 1998 2000 2002 2004 2006 2008 2010 2012 2014
2016( ଞωοτϫʔΫͱͷ࿈ܞ V ؒ௨৴ [ ϝογϡωοτϫʔΫ (11s) ແઢωοτϫʔΫཧ (11v) ແઢϦιʔεଌఆ (11k) %'451$ I "1ؒ௨৴ ' ߴϩʔϛϯά S ()[ଳ C ()[ଳ B ()[ଳߴԽ H ()[ଳߴԽ O ()[ଳରԠ BE ()[ଳߴԽ BD 2P4αϙʔτ F ཧϑϨʔϜ༗ઢ੍ޚ BF ηΩϡϦςΟ J ཧϑϨʔϜอޢ X ֤ࠃن੍ରԠ E K Z ҠಈମແઢΞΫηε Q ϏσΦૹ BB 578IJUF4QBDFରԠ BG 6)'ଳରԠ 5(BI தࠃϛϦଳରԠ 5(BK ߴॳظೝূ 5(BJ ϒϦοδػೳ֦ு 5(BL αʔϏεݕग़ػೳ֦ு 5(BR ()[ଳߴޮແઢ -"/ )&8 5(BY ()[ଳߴԽ 5(BZ ถࠃن੍ରԠ ()[ ຊपରԠ ()[ଳ ॳظن֨ -
802.11ͷྺ࢙ 2.4 GHz 5 GHz 1,000 100 10,000 10 Maximum
data rate (Mbits/s) 802.11 2 Mbits/s 802.11b 11 Mbits/s 802.11a 54 Mbits/s 802.11g 54 Mbits/s 802.11n 600 Mbits/s MIMO (x4) 802.11ac Wave 1 1.3 Gbits/s MIMO (x3) 802.11ac Wave 2 6.93 Gbits/s MIMO (x8) 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 802.11 2 Mbits/s 802.11a 54 Mbits/s 802.11g 54 Mbits/s 802.11n 600 Mbits/s MIMO (x4) 802.11ac Wave 1 1.3 Gbits/s MIMO (x3) 2013 2014 2015 802.11ac Wave 2 6.93 Gbits/s MIMO (x8) 802.11b 11 Mbits/s -
ଓϞʔυ • ΞΫηεϙΠϯτͷػೳΛιϑτΣΞͰ࣮ݱ͍ͯ͠Δɻ • ແઢͷଓઃఆʹ؆қଓํࣜʮWPSʯΛ༻͍ͯ͠Δɻ • ແઢػثͷSSIDʢݻ༗IDʣ҉߸ԽΩʔࣗಈతʹܾΊΒΕΔɻ • ௨৴͢Δແઢػثগͳ͘ͱҰํͷػث͕Wi-Fi DirectʹରԠ͠
͍ͯΕΑ͍ɻ • ʮ̍ରଟʯͷ௨৴ߦ͑Δɻୠ͠ɺಉ࣌ʹ௨৴Ͱ͖Δͷʮ̍ର ̍ʯͱͳΔɻ WDS -
҉߸ͱೝূ WEP WPA ϓϨγΣΞʔυΩʔ (WPA-PSK) WPA RADIUS (WPA Enterprise) ͳʹ͜Εʁ
WPA (TKIP) WPA2 (AES) WPA2 Mixed ͳʹ͜Εʁ ࠷ۙ͞Βʹɺ؆୯ઃఆͱ͍͏ AOSS WPS WPS2 ͕͋ͬͨΓ͢Δɻ ͳʹ͜Εʁ -
҉߸ํ๏ͷબ ҉߸ํ๏ ҉߸Խํࣜ ҉߸ԽΞϧΰϦζϜ WEP WEP 64bit RC4 WEP 128bit
RC4 WPA TKIP RC4 ( CCMP ) ( AES ) WPA2 ( TKIP ) ( RC4 ) CCMP AES ͜ΕҰ -
1998 2000 2002 2004 2006 2008 2010 2012 2014 2016(
()[ଳ C ()[ଳ B ()[ଳߴԽ H ()[ଳߴԽ O ()[ଳରԠ BE ()[ଳߴԽ BD 2P4αϙʔτ F ཧϑϨʔϜ༗ઢ੍ޚ BF ηΩϡϦςΟ J ཧϑϨʔϜอޢ X ϏσΦૹ BB ߴॳظೝূ 5(BJ ()[ଳߴޮແઢ -"/ )&8 5(BY ()[ଳߴԽ 5(BZ ॳظن֨ WEPͷ੬ऑੑ͕ࢦ ఠ͞Ε࢝ΊΔ IEEE 802.11i ࢝ಈ Wi-Fi Alliance͕͖ͪΕͣɺ 802.11iͷ%SBGUஈ֊Ͱೝূ ϓϩάϥϜΛ։࢝ 81" IEEE 802.11i ن֨Խ 81" Wi-Fi Alliance͕վΊͯਖ਼ࣜ JͷೝূϓϩάϥϜΛ ։࢝ 81" ҉߸ํ๏ͷબ WPAͱWPA2ࣅͯඇͳΔͷɻ -
ೝূํ๏ͷબ ೝূํ๏ ೝূํࣜ ೝূํࣜ WPA PSK खೖྗͷڞ༗伴 4way handshake WPA
Enterprise Ϣʔβೝূ 802.1x (EAPoL) MD5 LEAP PEAP FAST TTLS TLS … ແઢAP͕ɺRADIUSͱ͍͏֎෦αʔόʹ ଓͷՄ൱Λ͓͍ʹߦ͘ɻ ͦͷࡍͷೝূํ๏ͷબࢶཚཱ͍ͯͯ͠ ΧΦεɻ ແઢAPʹઃఆ͓͚ͯ͠OK ڞ༗伴Λ͍ͬͯΔਓ୭ͰଓՄೳ -
ૹํࣜ • ϕʔεόϯυૹ • ൖૹଳҬૹ ૹΓ͍ͨ৴߸ = ϕʔεόϯυ৴߸ • ͦͷ··ૹΔɻ༗ઢͰଟ͍ɻEther,
USB, … • ൖૹʹͤͯૹΔɻແઢͰଟ͍ɻ -
ίϯελϨʔγϣϯ BPSK QPSK ҰͭͷͰɺ̌ʙ3 ·Ͱͷ4छྨͷ৴߸( 00, 01, 10, 11 )
= 2bitͷใ͕ૹՄೳʂ -
802.11gͰͷ௨৴ • 1 symbol = 6 bit • 1 symbolૹ৴࣌ؒ(usec)
= 3.2 + 0.8 = 4.0 usec → symbol rate = 1/4.0 usec = 250k symbol/sec → 1αϒΩϟϦΞ͋ͨΓͷૹ৴Մೳbit ɹɹ6 bit/symbol x 250k symbol/sec = 1.5M bit/sec • σʔλૹՄೳͳαϒΩϟϦΞ : 48 → શαϒΩϟϦΞͰૹՄೳͳbit ɹ1.5M bit/sec x 48 = 72M bit/sec • ූ߸Խޮ : 3/4 → 72M bit/sec x 3/4 = 54M bit/sec -
802.11nͰͷ௨৴ • 1 symbol = 6 bit • 1 symbolૹ৴࣌ؒ(usec)
= 3.2 + 0.4 = 3.6 usec → symbol rate = 1/3.6 usec = 277.77k symbol/sec → 1αϒΩϟϦΞ͋ͨΓͷૹ৴Մೳbit ɹɹ6 bit/symbol x 277.77k symbol/sec = 1.666M bit/sec • σʔλૹՄೳͳαϒΩϟϦΞ : 108 → શαϒΩϟϦΞͰૹՄೳͳbit ɹ1.666M bit/sec x 108 = 180M bit/sec • ූ߸Խޮ : 5/6 → 180M bit/sec x 5/6 = 150M bit/sec • MIMOʹΑΔ4ετϦʔϜ → 150M bits/sec x 4ຊ = 600M bit/sec -
802.11nͰͷߴԽ ·ͱΊ OFDMͷ54MbpsͷσʔλϨʔτɺ্ͷ5߲ͷٕज़ʹΑͬͯ300MbpsʹͳΓ·͢ɻ ූ߸Խͷ্ʹΑͬͯɺͦΕ·Ͱ࠷େ3/4ͩͬͨූ߸Խ͕5/6ʹͳΓ·ͨ͠ɻ͜ΕʹΑΓɺσʔλϨʔτ͕(5/6)/(3/4)Ͱ10/9ഒʹͳΓ·͢ɻ αϒΩϟϦΞ૿Ճͱόϯυ෯40MHz༰తʹಉͰ͢ɻϋϯυ෯͕ഒʹͳΔ͜ͱͰɺαϒΩϟϦΞ͕૿͑ΔͨΊͰ͢ɻ ͜ͷͱ͖ɺݩʑσʔλ৴߸༻ʹ48ຊͩͬͨαϒΩϟϦΞ͕108ຊʹͳΓ·͢ɻͭ·Γɺ9/4ഒʹͳΓ·͢ɻ MIMOͷSDMʹΑΔ4ετϦʔϜ௨৴ʹΑͬͯɺσʔλϨʔτ͕4ഒʹͳΓ·͢ɻ ࠷ޙʹΨʔυΠϯλʔόϧͷॖʹΑͬͯɺσʔλϨʔτ͕4/3.6Ͱ10/9ഒʹͳΓ·͢ɻ ͢ͳΘͪɺ͜ΕΒΛ૯߹͢Δͱɺ࣍ͷΑ͏ͳܭࢉʹͳΓ·͢ɻ 54
× 10/9 × 9/4 × 4 × 10/9 ʹ 600 (Mbps) 11nͷσʔλϨʔτɺ͜ͷΑ͏ʹͯ͠600Mbps·ͰߴΊΒΕ͍ͯ·͢ɻ ͨͩ͠ɺ͜ΕཧͰ͋Γɺ11nͷ࣮ޮϨʔτΛߴΊΔͨΊʹͦͷ΄͔ʹɺA-MPDUͳͲͷϑϨʔϜΞάϦήʔγϣϯɺϒϩοΫACKͳͲɺͬͱଟ͘ͷ৽ٕज़͕༻͍ΒΕ͍ͯ·͢ɻ ͦΕʹΑΓɺ࣮ޮϨʔτ100MbpsΦʔόʔͷ11nͷߴ௨৴͕Ͱ͖ΔΘ͚Ͱ͢ɻ • ූ߸Խޮͷ্ • αϒΩϟϦΞͷ૿Ճ • όϯυ෯֦େ 40MHz (νϟωϧϘϯσΟϯά) • ΨʔυΠϯλʔόϧॖ • MIMOʹΑΔ4ετϦʔϜ௨৴ -
802.11acͰͷ௨৴ • 1 symbol = 8 bit • 1 symbolૹ৴࣌ؒ(usec)
= 3.2 + 0.4 = 3.6 usec → symbol rate = 1/3.6 usec = 277.77k symbol/sec → 1αϒΩϟϦΞ͋ͨΓͷૹ৴Մೳbit ɹɹ8 bit/symbol x 277.77k symbol/sec = 2.222M bit/sec • σʔλૹՄೳͳαϒΩϟϦΞ : 468 → શαϒΩϟϦΞͰૹՄೳͳbit ɹ 2.222M bit/sec x 468 = 1.04G bit/sec • ූ߸Խޮ : 5/6 → 1.04G bit/sec x 5/6 = 866.6M bit/sec • MIMOʹΑΔ8ετϦʔϜ → 866.6M bits/sec x 8ຊ = 6.9G bit/sec -
௨৴ํ๏ MACΞΫηεϞʔυ DCF : Distributed Coordination Function ɹɹɹCSMA/CAࣜ PCF :
Point Coordination Function ɹɹɹpollingࣜ (RTS/CTS) HCF : Hybrid Coordination Function ɹɹɹ802.11eͰنఆ ɹɹɹDCF + PCF ACK੍ޚํࣜ ඞͣACKͷฦૹΛͭɻ ͜ͳ͚Ε࠶ૹ͢Δɻ -
ΞυϨογϯά ྫ1 : ແઢػث → ແઢػثͷ௨৴ ྫ2 : ༗ઢػث →
ແઢػثͷ௨৴ ྫ3 : ແઢػث → ༗ઢػثͷ௨৴ ྫ4 : ༗ઢػث → ແઢ → ༗ઢػثͷ௨৴ Address1 ѼઌMAC Address2 ૹ৴ݩMAC Address3 #44*% Address4 -
ύέοτͷछྨ Packetछผ (ྫ) ํ Beacon AP → ST APɺಈ࡞͍ͯ͠Δνϟωϧ্ʹ௨ৗ100msecִؒͰ߃ৗతʹૹ৴͍ͯ͠·͢ɻ BSSID,
SSID, Ϗʔίϯૹ৴ִؒɺνϟωϧใɺηΩϡϦςΟใͳͲؚ͕·ͯ ͍·͢ɻ Probe Request ST → AP APબ Response AP → ST APબʢ༰΄΅Beaconͱಉ͡ʣ Authentication Request ST → AP ೝূཁٻʢݱࡏͰ΄΅ܗ֚Խʣ Response AP → ST ೝূཁٻԠʢݱࡏͰ΄΅ܗ֚Խʣ Association Request ST → AP ଓཁٻ Response AP → ST ଓڐՄԠ Data AP ←→ ST σʔλ -
APىಈ w "1 ػ Λىಈ͢Δ ▾ AP802.11n͕༗ޮͷ߹ w ઃఆ͞Εͨνϟωϧ
प ͰεΩϟϯΛߦ͍ɺϨΨγʔઃఆ O͕༗ޮͰͳ͍ ͷ"1͕ଘࡏ͢Δ͔Ͳ͏͔֬ೝ͢Δ ▾ APʹઃఆ͞Εͨνϟωϧ͕W53(5.3GHzଳ)/W56(5.6GHzଳ)ͷ߹ w ؾϨʔμʔͷిΛݕ͢ΔͨΊʹؒػ͢Δ w "1ઃఆ͞Εͨνϟωϧʹ͓͍ͯ#FBDPO ϚωʔδϝϯτϑϨʔϜϒϩʔυΩϟετ ΛNTFDִؒͰૹ৴࢝͠ΊΔ • ϨΨγʔઃఆͷAP͕ଘࡏ͢Δ߹ɺഒͷप(40MHz)ʹΑΔӡ༻͕ෆՄͰ͋Δ͜ͱΛBeaconʹΑͬͯ௨͢Δ(HT20/40 Coexistenceػೳ) w "1εςϧεઃఆͷ߹ɺ#FBDPOʹઃఆ͢Δ44*% &44*% Λۭจࣈ /6-- ͱ͢Δ -
APͷൃݟͱଓ։࢝·Ͱ • STA(ࢠػ)νϟωϧΛΓସ͑ͯεΩϟϯ͠ͳ͕ΒɺSTAʹઃఆ͞ΕͨSSIDΛ࣋ͭAPΛಛఆ͢Δ • STAProbe Request(ϚωʔδϝϯτϑϨʔϜ/͜ͷ߹ϒϩʔυΩϟετ)ʹSSIDΛઃఆ͠ɺAP͔ΒProbe Response(ϚωʔδϝϯτϑϨʔϜ/ ϢχΩϟετ)Λड͚Δ͜ͱͰεςϧεͷAPΛಛఆ͢Δ • STABeaconͷ֤ΤϨϝϯτʹઃఆ͞Εͨɺೝূํࣜ(Open/Shared/WPA-PSK/WPA2-PSK/WPA-EAP/WPA2-EAP)҉߸ํࣜ(WEP/AES/
TKIP)ɺαϙʔτ͢ΔσʔλసૹϨʔτɺͳͲΛ֬ೝ͢Δ • STAAuthenticationϑϨʔϜʢSharedೝূํࣜͷ߹"shared"ɺͦΕҎ֎"open"ΛઃఆʣΛAPʹૹ৴͢Δ ▾ Sharedೝূํࣜͷ߹ (WEP) • ʻলུʼ ▾ ͦΕҎ֎ͷೝূํࣜͷ߹ • APAuthenticationϑϨʔϜΛSTAʹૹ৴͢Δ • STAAssociation RequestϑϨʔϜΛAPʹૹ৴͢Δ • APAssociation ResponseϑϨʔϜΛSTAʹૹ৴͢Δ ▾ Openೝূํࣜʢೝূແ͠ʣ/Sharedೝূํࣜͷ߹ • ͜͜Ͱσʔλ௨৴͕ՄೳʹͳΔ ▾ WPA-EAP/WPS2-EAPೝূํࣜͷ߹ • 4way handshakeΛ࢝ΊΔ WEP͜͜Ͱ҉߸ใͷ ΓͱΓΛߦ͏ɻ ݱࡏܗ֚Խɻ -
҉߸ͱೝূ WEP WPA ϓϨγΣΞʔυΩʔ (WPA-PSK) WPA RADIUS (WPA Enterprise) ͳʹ͜Εʁ
WPA (TKIP) WPA2 (AES) WPA2 Mixed ͳʹ͜Εʁ ࠷ۙ͞Βʹɺ؆୯ઃఆͱ͍͏ AOSS WPS WPS2 ͕͋ͬͨΓ͢Δɻ ͳʹ͜Εʁ -
WPA Enterprise ೝূํࣜ આ໌ αʔόೝূ ΫϥΠΞϯτೝূ MD5 CHAP ͳ͠ CHAPʹΑΔUser/Passೝূ
LEAP CISCOಠࣗɹνϟϨϯδํࣜ ༷ඇެ։ ੬ऑੑ͋Γʢ͍͚ͬͯͳ͍ʣ νϟϨϯδํࣜ νϟϨϯδํࣜ PEAP CISCO, MS, RSA SecurityʹΑΔTTLSํࣜ v0, (v1, v2)͕ଘࡏ͢Δ͕ɺެࣜඪ४༷ॻଘࡏ͠ͳ͍ ূ໌ॻʹΑΔೝূ EAP (ͦͷதͷԿΛ༻͢Δ͔ఆ Ί͍ͯͳ͍ɻσϑΝΫτͱͯ͠ v0͔ͭMSCHAPv2) FAST RFC4851 (΄΅CISCOಠࣗ) αʔόূ໌ॻͳ͠ʹTTLSΛ࣮ݱ͢ΔLEAPͷൃలܥن֨ɻͨͩ͠ɺ ূ໌ॻ༻Λڧ͘ਪ͍ͯ͠ΔͨΊଘࡏҙ͕ٛෆ໌ɻ νϟϨϯδํࣜ ( MSCHAPv2 ) νϟϨϯδํࣜ ( MSCHAPv2 ) TTLS RFC5281(2008) αʔόূ໌ॻʹΑΔ҉߸τϯωϧͰΫϥΠΞϯτೝূΛߦ͏ ূ໌ॻʹΑΔೝূ PAP, CHAP, MSCHAP, MSCHAPv2, EAP TLS RFC5216(2008) ূ໌ॻʹΑΔೝূ ূ໌ॻʹΑΔೝূ ͦͷଞͷEAPϓϩτίϧ 0 Reserved 12 KEA-VALIDATE 24 EAP-3Com Wireless 36 Cogent Systems Biometrics Authentication EAP 48 EAP-SAKE 1 Identity 13 EAP-TLS 25 PEAP 37 AirFortress EAP 49 EAP-IKEv2 2 Notification 14 Defender Token (AXENT) 26 MS-EAP-Authentication 38 EAP-HTTP Digest 50 EAP-AKA' 3 Legacy Nak 15 RSA Security SecurID EAP 27 Mutual Authentication w/Key Exchange (MAKE) 39 SecureSuite EAP 51 EAP-GPSK 4 MD5-Challenge 16 Arcot Systems EAP 28 CRYPTOCard 40 DeviceConnect EAP 52 EAP-pwd 5 One-Time Password (OTP) 17 EAP-Cisco Wireless (LEAP) 29 EAP-MSCHAP-V2 41 EAP-SPEKE 53 EAP-EKE Version 1 6 Generic Token Card (GTC) 18 GSM Subscriber Identity Modules (EAP-SIM) 30 DynamID 42 EAP-MOBAC 54 EAP Method Type for PT-EAP 7 Allocated 19 SRP-SHA1 31 Rob EAP 43 EAP-FAST 55 TEAP 8 Allocated 20 Unassigned 32 Protected One-Time Password (POTP) 44 ZoneLabs EAP (ZLXEAP) 56-191 Unassigned 9 RSA Public Key Authentication 21 EAP-TTLS 33 MS-Authentication-TLV 45 EAP-Link 192-253 Unassigned 10 DSS Unilateral 22 Remote Access Service 34 SentriNET 46 EAP-PAX 254 Reserved for the Expanded Type 11 KEA 23 EAP-AKA Authentication 35 EAP-Actiontec Wireless 47 EAP-PSK 255 Experimental -
؆୯ઃఆ ํ๏ ن֨ ೝূํࣜ ૬ޓೝূ AOSS ಠࣗ WPSʹઌΜͯ͡ɺBUFFALOͷಠࣗن֨ Push ButtonʹΑΔೝূ
ָʑແઢελʔτ NECΞΫηεςΫχΧಠࣗ Push ButtonʹΑΔೝূ Jump Start Atheros Communicationಠࣗ Windows Connect Now MSಠࣗ (XP SP2, Win7) WPS Wi-Fi Alliance PBCํࣜ Push ButtonʹΑΔೝূ PINํࣜ PIN CodeʹΑΔೝূ WPS 2.0 WPS + Wi-Fi DirectରԠͳͲ -
ૹํࣜ • ϕʔεόϯυૹ • ൖૹଳҬૹ ૹΓ͍ͨ৴߸ = ϕʔεόϯυ৴߸ • ͦͷ··ૹΔɻ༗ઢͰଟ͍ɻEther,
USB, … • ʹͤͯૹΔɻແઢͰଟ͍ɻ ൖૹ ͲΜͳʁ ? -
ίϯελϨʔγϣϯ BPSK QPSK ҰͭͷͰɺ̌ʙ3 ·Ͱͷ4छྨͷ৴߸( 00, 01, 10, 11 )
= 2bitͷใ͕ૹՄೳʂ -
ଟॏํࣜ FHSS DSSS (+CCK) OFDM MIMO ॳ802.11 ͜Ε BT͜Ε ʢ༰লུʣ
802.11b ͜Ε ʢ༰লུʣ 802.11 a/g/n/ac ͜Ε 802.11 n/ac ͜Ε -
पಛੑ ASK Ͱ͋Ε QAM Ͱ͋ΕɺҙͷใܥྻΛ୯Ґ࣌ؒ T Ͱൖૹ fc ʹมௐΛ ͔͚ͨ߹ɺͦͷมௐͷऔΔपಛੑ(εϖΫτϥϜ)ԼਤͷΑ͏ʹ
ͳΔɻ 802.11g ҰͭͷγϯϘϧΛૹΔ࣌ؒ 3.2usec ͭ·Γɺ୯Ґ࣌ؒ T = 3.2usec 1/T = 312.5k ͜ΕΛαϒΩϟϦΞͱݺͼ·͢ɻ -
ύΠϩοτʢج४ʣ৴߸ͱͯ͠༻͍ΔͨΊσʔλͷͤͳ͍ɿຊ 312.5k ׂͣͭ͢Δͱɺ64ݸͷαϒΩϟϦΞ .L ͱͳΓͷνϟωϧप͔ΒӨڹΛड͚ͳ͍తͰΘͳ͍ ʢΨʔυόϯυʣ 6 5 தԝʢ-0ϦʔΫʣ Կނ͔Θͳ͍ຊ
ॏͶ߹Θͤ 802.11g 64ຊͷαϒΩϟϦΞͷ͏ͪɺ ҎԼ͑ͳ͍ɻ 1 : தԝ 4 : ύΠϩοτ༻ 6+5 : Ψʔυόϯυ༻ ͑Δͷ 48ຊ ! -
7 Encoding Process 00 00 10 00 01 10 11
00 01 10 11 00 01 10 11 00 01 10 11 00 01 00 0(00) 1(11) 0(10) 1(01) 1(10) 1(00) 0(11) 0(01) 0(00) 1(11) 0(10) 1(01) 1(10) 1(00) 0(11) 0(01) 0(00) 1(11) 0(10) 1(01) 1(10) 1(00) 0(11) 0(01) 0(00) 1(11) 1(10) 0(01) 0(00) 1(11) 0(00) 0(10) 0(11) 0(01) 0(00) 0(11) Input: 1 0 1 1 1 0 0 Output: 11 01 00 10 01 10 11 ΈࠐΈූ߸ͷΤϯίʔυ -
ΈࠐΈූ߸ͷσίʔυ ϏλϏΞϧΰϦζϜ 10 Viterbi Decoding Process 00 00 10 00
01 10 11 00 01 10 11 00 01 10 11 00 01 10 11 00 01 00 0(00) 1(11) 0(10) 1(01) 1(10) 1(00) 0(11) 0(01) 0(00) 1(11) 0(10) 1(01) 1(10) 1(00) 0(11) 0(01) 0(00) 1(11) 0(10) 1(01) 1(10) 1(00) 0(11) 0(01) 0(00) 1(11) 1(10) 0(01) 0(00) 1(11) 0(00) 0(10) 0(11) 0(01) 0(00) 0(11) Output: 11 01 00 10 01 10 11 Receive: 11 11 00 10 01 11 11 2 0 -
11 Viterbi Decoding Process 00 00 10 00 01 10
11 00 01 10 11 00 01 10 11 00 01 10 11 00 01 00 0(00) 1(11) 0(10) 1(01) 1(10) 1(00) 0(11) 0(01) 0(00) 1(11) 0(10) 1(01) 1(10) 1(00) 0(11) 0(01) 0(00) 1(11) 0(10) 1(01) 1(10) 1(00) 0(11) 0(01) 0(00) 1(11) 1(10) 0(01) 0(00) 1(11) 0(00) 0(10) 0(11) 0(01) 0(00) 0(11) Output: 11 01 00 10 01 10 11 Receive: 11 11 00 10 01 11 11 2 0 4 2 1 1 ΈࠐΈූ߸ͷσίʔυ ϏλϏΞϧΰϦζϜ -
12 Viterbi Decoding Process 00 00 10 00 01 10
11 00 01 10 11 00 01 10 11 00 01 10 11 00 01 00 0(00) 1(11) 0(10) 1(01) 1(10) 1(00) 0(11) 0(01) 0(00) 1(11) 0(10) 1(01) 1(10) 1(00) 0(11) 0(01) 0(00) 1(11) 0(10) 1(01) 1(10) 1(00) 0(11) 0(01) 0(00) 1(11) 1(10) 0(01) 0(00) 1(11) 0(00) 0(10) 0(11) 0(01) 0(00) 0(11) Output: 11 01 00 10 01 10 11 Receive: 11 11 00 10 01 11 11 2 0 4 2 1 1 3 2 1 2 ΈࠐΈූ߸ͷσίʔυ ϏλϏΞϧΰϦζϜ -
13 Viterbi Decoding Process 00 00 10 00 01 10
11 00 01 10 11 00 01 10 11 00 01 10 11 00 01 00 0(00) 1(11) 0(10) 1(01) 1(10) 1(00) 0(11) 0(01) 0(00) 1(11) 0(10) 1(01) 1(10) 1(00) 0(11) 0(01) 0(00) 1(11) 0(10) 1(01) 1(10) 1(00) 0(11) 0(01) 0(00) 1(11) 1(10) 0(01) 0(00) 1(11) 0(00) 0(10) 0(11) 0(01) 0(00) 0(11) Output: 11 01 00 10 01 10 11 Receive: 11 11 00 10 01 11 11 2 0 4 2 1 1 3 2 1 2 3 2 3 1 ΈࠐΈූ߸ͷσίʔυ ϏλϏΞϧΰϦζϜ -
14 Viterbi Decoding Process 00 00 10 00 01 10
11 00 01 10 11 00 01 10 11 00 01 10 11 00 01 00 0(00) 1(11) 0(10) 1(01) 1(10) 1(00) 0(11) 0(01) 0(00) 1(11) 0(10) 1(01) 1(10) 1(00) 0(11) 0(01) 0(00) 1(11) 0(10) 1(01) 1(10) 1(00) 0(11) 0(01) 0(00) 1(11) 1(10) 0(01) 0(00) 1(11) 0(00) 0(10) 0(11) 0(01) 0(00) 0(11) Output: 11 01 00 10 01 10 11 Receive: 11 11 00 10 01 11 11 2 0 4 2 1 1 3 2 1 2 3 2 3 1 3 3 3 1 ΈࠐΈූ߸ͷσίʔυ ϏλϏΞϧΰϦζϜ -
15 Viterbi Decoding Process 00 00 10 00 01 10
11 00 01 10 11 00 01 10 11 00 01 10 11 00 01 00 0(00) 1(11) 0(10) 1(01) 1(10) 1(00) 0(11) 0(01) 0(00) 1(11) 0(10) 1(01) 1(10) 1(00) 0(11) 0(01) 0(00) 1(11) 0(10) 1(01) 1(10) 1(00) 0(11) 0(01) 0(00) 1(11) 1(10) 0(01) 0(00) 1(11) 0(00) 0(10) 0(11) 0(01) 0(00) 0(11) Output: 11 01 00 10 01 10 11 Receive: 11 11 00 10 01 11 11 2 0 4 2 1 1 3 2 1 2 3 2 3 1 3 3 3 1 3 2 ΈࠐΈූ߸ͷσίʔυ ϏλϏΞϧΰϦζϜ -
16 Viterbi Decoding Process 00 00 10 00 01 10
11 00 01 10 11 00 01 10 11 00 01 10 11 00 01 00 0(00) 1(11) 0(10) 1(01) 1(10) 1(00) 0(11) 0(01) 0(00) 1(11) 0(10) 1(01) 1(10) 1(00) 0(11) 0(01) 0(00) 1(11) 0(10) 1(01) 1(10) 1(00) 0(11) 0(01) 0(00) 1(11) 1(10) 0(01) 0(00) 1(11) 0(00) 0(10) 0(11) 0(01) 0(00) 0(11) Output: 11 01 00 10 01 10 11 Receive: 11 11 00 10 01 11 11 2 0 4 2 1 1 3 2 1 2 3 2 3 1 3 3 3 1 3 2 2 ΈࠐΈූ߸ͷσίʔυ ϏλϏΞϧΰϦζϜ -
17 Viterbi Decoding Process 00 00 10 00 01 10
11 00 01 10 11 00 01 10 11 00 01 10 11 00 01 00 0(00) 1(11) 0(10) 1(01) 1(10) 1(00) 0(11) 0(01) 0(00) 1(11) 0(10) 1(01) 1(10) 1(00) 0(11) 0(01) 0(00) 1(11) 0(10) 1(01) 1(10) 1(00) 0(11) 0(01) 0(00) 1(11) 1(10) 0(01) 0(00) 1(11) 0(00) 0(10) 0(11) 0(01) 0(00) 0(11) Decision:11 01 00 10 01 10 11 Receive: 11 11 00 10 01 11 11 2 0 4 2 1 1 3 2 1 2 3 2 3 1 3 3 3 1 3 2 2 Output: 1011100 ΈࠐΈූ߸ͷσίʔυ ϏλϏΞϧΰϦζϜ -
802.11gͰͷ௨৴ • 1 symbol = 6 bit • 1 symbolૹ৴࣌ؒ(usec)
= 3.2 + 0.8 = 4.0 usec → symbol rate = 1/4.0 usec = 250k symbol/sec → 1αϒΩϟϦΞ͋ͨΓͷૹ৴Մೳbit ɹɹ6 bit/symbol x 250k symbol/sec = 1.5M bit/sec • σʔλૹՄೳͳαϒΩϟϦΞ : 48 → શαϒΩϟϦΞͰૹՄೳͳbit ɹ1.5M bit/sec x 48 = 72M bit/sec • ූ߸Խޮ : 3/4 → 72M bit/sec x 3/4 = 54M bit/sec -
802.11nͰͷߴԽ • όϯυ෯֦େ 40MHz (νϟωϧϘϯσΟϯά) • αϒΩϟϦΞͷ૿Ճ • ΨʔυΠϯλʔόϧॖ •
ූ߸Խޮͷ্ • MIMOʹΑΔ࠷େ4ετϦʔϜ௨৴ -
5480 5500 5520 5540 5560 5580 प .)[ 5600 5620
5640 5660 5680 5700 W56 100ch (5.50GHz) 104ch (5.52GHz) 108ch (5.54GHz) 112ch (5.56GHz) 116ch (5.58GHz) 120ch (5.60GHz) 124ch (5.62GHz) 128ch (5.64GHz) 132ch (5.66GHz) 136ch (5.68GHz) 140ch (5.70GHz) όϯυ෯֦େ 40MHz 5160 5180 5200 5220 5240 5260 प .)[ 5280 5300 5320 36ch (5.18GHz) 40ch (5.20GHz) 44ch (5.22GHz) 48ch (5.24GHz) 52ch (5.26GHz) 56ch (5.28GHz) 60ch (5.30GHz) 64ch (5.32GHz) W52 W53 -
ύΠϩοτʢج४ʣ৴߸ͱͯ͠༻͍ΔͨΊσʔλͷͤͳ͍ɿຊ 312.5k ׂͣͭ͢Δͱɺ64ݸͷαϒΩϟϦΞ .L ͱͳΓͷνϟωϧप͔ΒӨڹΛड͚ͳ͍తͰΘͳ͍ ʢΨʔυόϯυʣ 4 3 தԝʢ-0ϦʔΫʣ Կނ͔Θͳ͍ຊ
αϒΩϟϦΞͷ૿Ճ (20MHz) 802.11n 64ຊͷαϒΩϟϦΞͷ͏ͪɺ ҎԼ͑ͳ͍ɻ 1 : தԝ 4 : ύΠϩοτ༻ 4+3 : Ψʔυόϯυ༻ ͑Δͷ 52ຊ ! -
ύΠϩοτʢج४ʣ৴߸ͱͯ͠༻͍ΔͨΊσʔλͷͤͳ͍ɿຊ 312.5k ׂͣͭ͢Δͱɺ128ݸͷαϒΩϟϦΞ .L ͱͳΓͷνϟωϧप͔ΒӨڹΛड͚ͳ͍తͰΘͳ͍ ʢΨʔυόϯυʣ 6 5 தԝʢ-0ϦʔΫʣ Կނ͔Θͳ͍ຊ
αϒΩϟϦΞͷ૿Ճ (40MHz) 802.11n 128ຊ ͷαϒΩϟϦΞͷ͏ͪɺ ҎԼ͑ͳ͍ɻ 3 : தԝ 6 : ύΠϩοτ༻ 6+5 : Ψʔυόϯυ༻ ͑Δͷ 108ຊ ! -
802.11nͰͷ௨৴ • 1 symbol = 6 bit • 1 symbolૹ৴࣌ؒ(usec)
= 3.2 + 0.4 = 3.6 usec → symbol rate = 1/3.6 usec = 277.77k symbol/sec → 1αϒΩϟϦΞ͋ͨΓͷૹ৴Մೳbit ɹɹ6 bit/symbol x 277.77k symbol/sec = 1.666M bit/sec • σʔλૹՄೳͳαϒΩϟϦΞ : 108 → શαϒΩϟϦΞͰૹՄೳͳbit ɹ1.666M bit/sec x 108 = 180M bit/sec • ූ߸Խޮ : 5/6 → 180M bit/sec x 5/6 = 150M bit/sec • MIMOʹΑΔ4ετϦʔϜ → 150M bits/sec x 4ຊ = 600M bit/sec -
802.11nͰͷߴԽ ·ͱΊ OFDMͷ54MbpsͷσʔλϨʔτɺ্ͷ5߲ͷٕज़ʹΑͬͯ300MbpsʹͳΓ·͢ɻ ූ߸Խͷ্ʹΑͬͯɺͦΕ·Ͱ࠷େ3/4ͩͬͨූ߸Խ͕5/6ʹͳΓ·ͨ͠ɻ͜ΕʹΑΓɺσʔλϨʔτ͕(5/6)/(3/4)Ͱ10/9ഒʹͳΓ·͢ɻ αϒΩϟϦΞ૿Ճͱόϯυ෯40MHz༰తʹಉͰ͢ɻϋϯυ෯͕ഒʹͳΔ͜ͱͰɺαϒΩϟϦΞ͕૿͑ΔͨΊͰ͢ɻ ͜ͷͱ͖ɺݩʑσʔλ৴߸༻ʹ48ຊͩͬͨαϒΩϟϦΞ͕108ຊʹͳΓ·͢ɻͭ·Γɺ9/4ഒʹͳΓ·͢ɻ MIMOͷSDMʹΑΔ4ετϦʔϜ௨৴ʹΑͬͯɺσʔλϨʔτ͕4ഒʹͳΓ·͢ɻ ࠷ޙʹΨʔυΠϯλʔόϧͷॖʹΑͬͯɺσʔλϨʔτ͕4/3.6Ͱ10/9ഒʹͳΓ·͢ɻ ͢ͳΘͪɺ͜ΕΒΛ૯߹͢Δͱɺ࣍ͷΑ͏ͳܭࢉʹͳΓ·͢ɻ 54
× 10/9 × 9/4 × 4 × 10/9 ʹ 600 (Mbps) 11nͷσʔλϨʔτɺ͜ͷΑ͏ʹͯ͠600Mbps·ͰߴΊΒΕ͍ͯ·͢ɻ ͨͩ͠ɺ͜ΕཧͰ͋Γɺ11nͷ࣮ޮϨʔτΛߴΊΔͨΊʹͦͷ΄͔ʹɺA-MPDUͳͲͷϑϨʔϜΞάϦήʔγϣϯɺϒϩοΫACKͳͲɺͬͱଟ͘ͷ৽ٕज़͕༻͍ΒΕ͍ͯ·͢ɻ ͦΕʹΑΓɺ࣮ޮϨʔτ100MbpsΦʔόʔͷ11nͷߴ௨৴͕Ͱ͖ΔΘ͚Ͱ͢ɻ • ූ߸Խޮͷ্ • αϒΩϟϦΞͷ૿Ճ • όϯυ෯֦େ 40MHz (νϟωϧϘϯσΟϯά) • ΨʔυΠϯλʔόϧॖ • MIMOʹΑΔ4ετϦʔϜ௨৴ -
802.11acͰͷߴԽ • αϒΩϟϦΞͷ૿Ճ • όϯυ෯֦େ 160MHz (νϟωϧϘϯσΟϯά) • มௐ৴߸ͷଟԽ (256QAM)
• MIMOʹΑΔ࠷େ8ετϦʔϜ௨৴ -
ύΠϩοτʢج४ʣ৴߸ͱͯ͠༻͍ΔͨΊσʔλͷͤͳ͍ɿຊ 312.5k ׂͣͭ͢Δͱɺ512ݸͷαϒΩϟϦΞ .L ͱͳΓͷνϟωϧप͔ΒӨڹΛड͚ͳ͍తͰΘͳ͍ ʢΨʔυόϯυʣ 6 5 தԝʢ-0ϦʔΫʣ Կނ͔Θͳ͍ຊ
3 3 αϒΩϟϦΞͷ૿Ճ (160MHz) 802.11ac 512ຊͷαϒΩϟϦΞͷ͏ͪɺ ҎԼ͑ͳ͍ɻ 11 : தԝ 16 : ύΠϩοτ༻ 6+3+3+5 : Ψʔυόϯυ༻ ͑Δͷ 468ຊ ! -
5480 5500 5520 5540 5560 5580 प .)[ 5600 5620
5640 5660 5680 5700 W56 100ch (5.50GHz) 104ch (5.52GHz) 108ch (5.54GHz) 112ch (5.56GHz) 116ch (5.58GHz) 120ch (5.60GHz) 124ch (5.62GHz) 128ch (5.64GHz) 132ch (5.66GHz) 136ch (5.68GHz) 140ch (5.70GHz) 5160 5180 5200 5220 5240 5260 प .)[ 5280 5300 5320 36ch (5.18GHz) 40ch (5.20GHz) 44ch (5.22GHz) 48ch (5.24GHz) 52ch (5.26GHz) 56ch (5.28GHz) 60ch (5.30GHz) 64ch (5.32GHz) W52 W53 όϯυ෯֦େ 160MHz -
802.11acͰͷ௨৴ • 1 symbol = 8 bit • 1 symbolૹ৴࣌ؒ(usec)
= 3.2 + 0.4 = 3.6 usec → symbol rate = 1/3.6 usec = 277.77k symbol/sec → 1αϒΩϟϦΞ͋ͨΓͷૹ৴Մೳbit ɹɹ8 bit/symbol x 277.77k symbol/sec = 2.222M bit/sec • σʔλૹՄೳͳαϒΩϟϦΞ : 468 → શαϒΩϟϦΞͰૹՄೳͳbit ɹ 2.222M bit/sec x 468 = 1.04G bit/sec • ූ߸Խޮ : 5/6 → 1.04G bit/sec x 5/6 = 866.6M bit/sec • MIMOʹΑΔ8ετϦʔϜ → 866.6M bits/sec x 8ຊ = 6.9G bit/sec -
άϦʔϯϑΟʔϧυϞʔυ • Long Preamble : 192usec • Short Preamble :
96usec • ERP-ODFM Preamble : 20usec -
802.11e (QoS) • AC_VO (Voice) • AC_VI (Video) • AC_BE
(Best Effort) • AC_BK (Background) IPϔομͷTOS (Type of Service)ɺ802.11QͰنఆ͞ΕΔVLAN-TagͷϓϥΠΦϦςΟͷΛ 4ͭͷACʹׂΓͯΔͳͲͰ༏ઌ͚͢Δɻ ૹ৴ํࣜͱͯ͠ɺҎԼͷ͕̎ͭ͋Δɻ • EDCAํࣜ • HCCAํࣜ -
QoS EDCAํࣜ • EDCAํࣜ : Enhanced Distributed Channel Access WME
(Wireless Multimedia Extensions)Ͱ࠾༻ -
QoS HCCAํࣜ • HCCAํࣜ : HCF (Hybrid Coordination Function) Controlled
Channel Access WSM (Wireless Scheduled Multimedia)Ͱ࠾༻ -
ϩʔϛϯά ؔ࿈ن֨ આ໌ 802.11f IAPP : APؒ௨৴ 2001ʹऴྃ 802.11k ແઢϦιʔεଌఆ
802.11r ߴϩʔϛϯά 802.11fΛҾ͖ܧ͍ͰɺͷҠಈޙͰ࠶ೝূαʔόʹ͍ ߹ΘͤͣʹࡁΉΑ͏ʹɺΞΫηεϙΠϯτؒͰೝূใΛ ަ͢Δϓϩτίϧ͕نఆ͞Ε͍ͯΔɻ -
802.11k AP1 AP2 AP3 AP4 ᶃ ᶄ ᶅ ᶆ ᶃ
ΞΫηεϙΠϯτ͔̍Βϊʔτ̥̘ʹΞΫηεϙΠϯτͷมߋΛ௨ ᶄ ࠷దͳΞΫηεϙΠϯτΛ୳͢ཁٻΛग़͢ ᶅ ̖̥͔̍Βແઢڥʹؔ͢Δใ͕ૹΒΕͯ͘Δ ᶆ ͜ͷϊʔτ̥̘̖̥̎Λબͼɺ࠷దͳ௨৴͕ग़དྷΔ -
802.11r Intra Controller Roam Inter Controller Roam Over The Air
Over The DS (Distributed System)