QoS
੍ޚΛߟྀͨ͠
DSR
ϓϩτίϧ֦ுͷҰߟ
A Study on Extensions of DSR Protocol Considering QoS Controls
ҏ౻ խ
†Masaru ITOH
Abstract: This paper discusses some extensions of DSR (Dynamic Source Routing) protocol to consider
QoS (Quality of Service) controls. IEEE 802.11e is wireless LAN standards for QoS. It specifies two functions, that is, EDCA (Enhanced Distributed Channel Access) and HCCA (Hybrid coordination function Controlled Channel Access). EDCA has two modes; one is an ad hoc mode and the other is an infrastructure mode. The proposed method focuses on the ad hoc mode in EDCA that classifies all data-frames into four access categories such as voice, video, text, or background. These access categories are indicated by AC VO, AC VI, AC BE, and AC BK, respectively. They are associated with contention windows that have an effect on setting a back-off time. So firstly, I propose a method for dynamically changing a range of contention windows after getting the number of neighbors of the node. Secondly, I propose three features adding to the original DSR protocol so as to consider QoS in the followings: 1) the first feature is to put an access category into an option field of control packets for DSR, 2) the second is to manage route-caches using only RREP packets, and 3) the last is to limit the hop-count metric.
1.
͡Ίʹ
IEEE 802.11ແઢLAN1, 2)ͷΞΫηε੍ޚʹࣗ ࢄ੍ޚͱूத੍ޚͷ2͕ͭ͋ΔɻલऀΛDCF (Distributed Coordination Function)ɺޙऀΛPCF (Point Coordination Function)ͱ͍͏ɻDCFΞΫηεϙΠϯτΛͨͣɺPCF ΞΫηεϙΠϯτʢػʣ͕ॱʹࢠػʹ͍߹Θͤͯʢ͜ ΕΛϙʔϦϯάͱ͍͏ʣɺԠͷ͋ͬͨࢠػʹૹ৴ݖΛ༩͑ ΔɻຊߘͰࣗࢄ੍ޚΛݚڀରͱ͢Δɻ ௨৴ΤϦΞͰ࣮ࡍʹૹड৴Ͱ͖Δͷ1ରͷϊʔυ͚ͩ Ͱ͋Δɻଞͷϊʔυͦͷؒɺνϟωϧ͕༻தʢBusy:Ϗ δʔʣͰ͋ΔͷͰɺΞΠυϧঢ়ଶʢIdle: ະ༻ঢ়ଶʣʹͳ Δ·Ͱ࣍ͷૹ৴ΛԆظ͢Δ͜ͱʹͳΔɻ͜Ε͕CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) ํࣜ 2)ͷࣗࢄ੍ޚͰ͋Δɻ
ۙɺແઢLANͰϚϧνϝσΟΞϦΞϧλΠϜͷσʔ λΛૹड৴͢ΔΈ͕ཁٻ͞ΕΔΑ͏ʹͳͬͨɻ͜ͷΑ͏ ͳQoS (Quality of Service)Λ࣮ݱ͢Δن֨ͱͯ͠ IEEE 802.11e3)͕͋Δɻඪ४Խ࡞ۀ20059݄ʹ͍ྃͯ͠ Δɻ͜ΕʹEDCA (Enhanced Distributed Channel Ac-cess)ͱHCCA (Hybrid Coordination Function Controlled Channel Access)͕نఆ͞Ε͍ͯΔɻEDCAैདྷͷDCF ͷ֦ுͰ͋ΓɺHCCAैདྷͷPCFͷ֦ுͱଊ͑Δ͜ͱ͕ Ͱ͖Δɻ͜͜Ͱεϧʔϓοτͷ্Λࢦ͠ɺEDCAΛ ͞Βʹ͖Ίࡉ੍͔͘ޚ͢Δํ๏ΛఏҊ͢Δɻ
IEEE 802.11eϊʔυؒಉ࢜Ͱ௨৴͠߹͏ɺϦ ϯΫϓϩτίϧ(Direct Link Protocol)4)Λنఆ͍ͯ͠Δ
†Ѫۀେֶ ܦӦใՊֶ෦ ใՊֶՊ(๛ాࢢ) ʹա͗ͳ͍ɻҰํɺ֤ϊʔυ͕ࣗࢄతʹ௨৴͠߹͏Ξυ ϗοΫωοτϫʔΫͰɺதܧϊʔυΛհͯ͠௨৴͢ΔϚϧ νϗοϓػೳΛඋ͍͑ͯΔͷ͕ҰൠతͰ͋Δɻૹ৴ݩϊʔυ ͔Βͷ௨৴ཁٻޙʹதܧϊʔυΛհ͠ɺѼઌϊʔυ·Ͱͷܦ ࿏Λ୳ࡧ͢ΔϦΞΫςΟϒܕϧʔςΟϯάϓϩτίϧͷͻͱ ͭʹDSR (Dynamic Source Routing)ϓϩτίϧ 5)͕͋ Δɻ͔͠͠ɺDSRϓϩτίϧIEEE 802.11eରԠϊʔυ ͷར༻Λఆ͍ͯ͠ͳ͍ɻͦ͜ͰɺIEEE 802.11eରԠϊʔ υͰར༻Ͱ͖ΔΑ͏ʹDSRϓϩτίϧΛ֦ு͢Δɻ͜Ε͕ 2ͭͷఏҊͰ͋Δɻ
DCFͰίϯςϯγϣϯΟϯυ (CW:Contention Window) ͱݺΕΔਖ਼۠ؒ [CWmin, CWmax] ʹଐ͢Δ ཚΛൃੜͤ͞ɺόοΫΦϑ࣌ؒͱݺΕΔૹ৴ִؒ࣌ؒ Λܾఆͯ͠ɺϊʔυؒͷΞΫηε੍ޚΛߦ͍ͬͯΔɻৄࡉ ʹ͍ͭͯޙड़͢ΔɻIEEE 802.11eͰɺσʔλछผ͝ ͱͷ༏ઌૹ৴ΛՄೳʹ͢ΔͨΊʹEDCAΛઃ͚͍ͯΔɻ EDCAͰσʔλछผΛ༏ઌॱʹԻ(AC VO)ɺϏσ Φ(AC VI)ɺϕετΤϑΥʔτ(AC BE)͓ΑͼόοΫάϥ ϯυ(AC BK)ͷ4ͭͷΞΫηεΧςΰϦ(AC: Access Category) ʹྨ͢Δɻ௨ৗɺද1ͷΑ͏ͳEDCAύϥ ϝʔλ 6)ͰίϯςϯγϣϯΟϯυΛنఆ͢Δ͜ͱ͕ଟ ͍ɻࣈεϩοτλΠϜͰ͋ΔɻEDCAͷύϑΥʔϚ ϯεʹؔͯ͠ɺYiΒ 7)ͷจ͕ৄ͍͠ɻ
LucaΒ 8)EDCAແઢLANΤϦΞʹIEEE 802.11e ඇରԠϊʔυ͕ଘࡏ͢Δ߹ͰɺΞΫηεϙΠϯτ͕ACK Λແࢹ͢ΕͦͷӨڹΛΒ͛Δ͜ͱ͕Ͱ͖Δ͜ͱΛఏҊ͠ ͍ͯΔɻ༏ઌͷߴ͍ԻϏσΦσʔλͷૹ৴࣌ʹɺί ϯςϯγϣϯΟϯυͷ෯͕ڱ͍ͨΊɺૹ৴ϊʔυ͕૿͑ ΔͱϑϨʔϜিಥ͕ߴ͘ͳΔɻIEEE 802.11eͷΠϯϑϥ
ετϥΫνϟϞʔυͰͷϑϨʔϜিಥΛվળ͢ΔՏଜΒ 9) ͷݚڀ͋ΔɻͲͪΒIEEE 802.11eͷΞυϗοΫϞʔυ Ͱͷར༻ߟྀ͍ͯ͠ͳ͍ɻఏҊ๏ͰΞΫηεϙΠϯτΛ հ͞ͳ͍ΞυϗοΫϞʔυͰͷϑϨʔϜিಥΛݮΒ͢ͱ͍͏ ࢹͰΛଊ͍͑ͯΔɻ͜ͷͰઌߦݚڀͷLucaΒ 8) ՏଜΒ 9)ͷํࡦͱҟͳΔɻ ΞυϗοΫωοτϫʔΫͰIEEE 802.11eରԠϊʔυΛར ༻͢Δ͜ͱʹΑΓɺૹ৴ϊʔυσʔλछผ͝ͱʹ༏ઌతʹ σʔλΛૹ৴Ͱ͖Δɻ͔͠͠தܧϊʔυ͕IEEE 802.11eඇ ରԠϊʔυͷ߹ɺ࣍ϗοϓͷ௨৴ैདྷͷDCFͱͳΓɺ ༏ઌతʹσʔλΛૹ৴Ͱ͖ͳ͍ɻ͔ͩΒDCF༻ʹઃܭ͞Ε ͨDSRϓϩτίϧͷ֦ு͕ඞཁͱͳΔͷͰ͋Δɻ Ҏ߱Ͱɺ2ষͰDSRϓϩτίϧͷ֦ுɺ3ষͰIEEE 802.11eΞυϗοΫϞʔυͷ֦ுʹ͍ͭͯͦΕͧΕఏҊ͢ Δɻ4ষͰੑೳධՁͰඞཁͱͳΔϑϨʔϜিಥͱεϧʔ ϓοτͷࢉఆ๏ʹ͍ͭͯड़Δɻ5ষͰఏҊ๏ͷੑೳධՁ ΛγϛϡϨʔγϣϯͰߦ͍ɺͦͷ݁Ռʹ͍ͭͯߟ͢Δɻ࠷ ޙʹ6ষͰ·ͱΊͱࠓޙͷ՝ʹ͍ͭͯड़Δɻ ঘɺຊߘୈ5ճใՊֶٕज़ϑΥʔϥϜͰൃදͨ͠༰ 10)ʹେ෯ͳՃචमਖ਼Λ༩͑ɺγϛϡϨʔγϣϯ݁Ռʹؔ͠ ͯΑΓৄࡉͳߟΛ༩͑ͨͷͰ͋Δɻ
2. DSR
ϓϩτίϧͷ֦ு
DSRϓϩτίϧΛIEEE 802.11eରԠϊʔυʹద༻͠ɺϦ ΞϧλΠϜσʔλϚϧνϝσΟΞσʔλͳͲͷૹʹ͏ ʹΦϦδφϧͷDSRϓϩτίϧΛ֦ு͢Δඞཁ͕͋Δɻ 2ɾ1 DSRϔομͷΦϓγϣϯྖҬͷར༻ ૹ৴ݩϊʔυ͕ϏσΦͳͲͷϚϧνϝσΟΞσʔλΛૹΔ ௨৴ཁٻͰ͋ΕɺIEEE 802.11eͷEDCAνϟωϧΞΫη εͷAC VIΞΫηεΧςΰϦͰRREQ (Route Request) ύέοτΛૹ৴͢ΔɻϝʔϧͳͲͷඇϦΞϧλΠϜσʔλͰ ͋ΕɺैདྷͷDCFνϟωϧΞΫηεʹ૬͢ΔAC BE ΞΫηεΧςΰϦͰRREQύέοτΛૹ৴͢ΔɻRREQύ έοτΛड৴ͨ͠ϊʔυɺ࣍ϗοϓRREQύέοτΛ ૹ৴͢Δ࣌ɺͦͷΞΫηεΧςΰϦͰૹ৴͢ΔɻͦΕʹ ਤ1ͷΑ͏ʹDSRϔομͷΦϓγϣϯྖҬʹΞΫηεΧς ΰϦΛ֨ೲͯ͠ɺRREQύέοτΛૹ৴͢ΕΑ͍ɻ RREQ ύ έ ο τ Λ ड ৴ ͠ ͨ த ܧ ϊ ʔ υ ͕ ࣍ ϗ ο ϓ ʹ RREQύέοτΛૹ৴͢Δࡍʹɺਤ2ͷΑ͏ʹRREQ ύέοτͷDSRϔομͷΦϓγϣϯྖҬ͔ΒΞΫηεΧ ςΰϦΛಘͯɺͦͷσʔλछผʹैͬͯRREQύέοτ ද1ίϯςϯγϣϯΟϯυͷσϑΥϧτνϟωϧΞΫηεछผ CWmin CWmax AIFS
EDCA (AC VO) 7 15 2 EDCA (AC VI) 15 31 2 EDCA (AC BE) 31 1023 3 EDCA (AC BK) 31 1023 7
AIFS: Arbitration Inter-Frame Space
Λૹ৴͢Δ͜ͱʹͳΔɻRREQύέοτΛड৴ͨ͠ϊʔυ ͕IEEE 802.11eඇରԠͰ͔ͭड৴ͨ͠ΞΫηεΧςΰϦ ͕AC VI·ͨAC VOͰ͋ͬͨ߹ʹɺ࣍ϗοϓͷ RREQύέοτͷૹ৴ߦΘͳ͍ɻ 2ɾ2 IEEE 802.11eରԠϧʔτΩϟογϡ DSRϓϩτίϧͰɺૹ৴ઌϊʔυ͕RREQύέοτΛ ड৴͢ΔͱɺRREP (Route Reply)ύέοτΛฦ৴͢Δ͕ɺ ૹ৴ݩϊʔυʹฦ৴͞ΕΔRREPύέοτ1͚ͭͩͱ ݶΒͳ͍ɻෳͷϊʔυ͔ΒRREPύέοτ͕ฦ৴͞Εͯ ͘Δ͜ͱ͋ΓಘΔɻDSRϓϩτίϧͰ࠷ॳʹड৴ͨ͠ RREPύέοτʹՃ͞Ε͍ͯΔܦ࿏ɺ·ͨ࠷ϗοϓ ͷܦ࿏Ͱύέοτૹ৴ΛࢼΈΔ͜ͱʹͳ͍ͬͯΔɻ ܦ࿏͕ܾ·͔ͬͯΒͷRREPύέοτͷׂɺૹ৴ݩ ϊʔυɺѼઌϊʔυ͓Αͼதܧϊʔυ͕࣋ͭϧʔτΩϟο γϡͷܦ࿏ใΛՃɾߋ৽͢Δ͜ͱͰ͋Δɻϊʔυ͕࣋ ͭϧʔτΩϟογϡɺRREPύέοτҎ֎ʹɺRREQύ έοτʹՃ͞Ε͍ͯΔܦ࿏ϧʔτΩϟογϡʹՃ͞Ε ΔͨΊɺϧʔτΩϟογϡසൟʹߋ৽͞ΕΔɻ ͔͠͠ɺϧʔτΩϟογϡͷهԱҬݶΒΕ͍ͯΔɻϦϯ ΫΕͨ͠ࡍͷସܦ࿏ใ͕ਖ਼͍͠อূͳ͍ɻϦϯΫ Ε࣌Ͱதܧϊʔυ͕ফ໓͍ͯ͠ΔՄೳੑ͕͋Δ͔ΒͰ͋ Δɻͦͷ߹࠶ɺܦ࿏୳ࡧΛߦΘͳͯ͘ͳΒͳ͍ɻ ͦ͜Ͱɺ·ͣɺRREPύέοτΛडऔͬͨϊʔυɺͦ ͷύέοτʹՃ͞Ε͍ͯΔܦ࿏ͷΈΛϧʔτΩϟογϡ ͢Δ͜ͱΛఏҊ͢Δɻ͞Βʹɺͦͷܦ࿏্ʹ͋Δதܧϊʔ υ͕ͯ͢IEEE 802.11eରԠϊʔυͰ͋Δܦ࿏ͷΈΛϧʔ τΩϟογϡͷରͱ͢Δ͜ͱซͤͯఏҊ͢Δɻཧ༝ ϊʔυফ໓࣌ʹଞͷܦ࿏Ͱͷૹ৴Λ࠶։͍ͨ͠ͱ͖ʹɺͦ ͷܦ࿏ͰσʔλछผʹΑΔ༏ઌૹ৴͕ՄೳͰ͋Δ͔൱͔Λ ѲͰ͖ΔΑ͏ʹ͢ΔͨΊͰ͋Δɻ͜ΕΒ2Λຬ͢Δ ϧʔτΩϟογϡΛ͜͜ͰಛʹɺIEEE 802.11eରԠϧʔ τΩϟογϡͱݺͿ͜ͱʹ͢Δɻ B A S AC_VOANZX RouteRequest (RREQ) MpPbgÌDSRwb_ ANZXJeS AC_VO IvVÌæ ਤ1 RREQύέοτͷૹ৴ B A S RouteRequest (RREQ) óMpPbgÌDSRwb_ QÆ AC_VOANZX ANZXJeS AC_VO IvVÌæ ਤ2 RREQύέοτͷதܧ
F A B C D H G E A-B-C-D A-E-F-D A-G-H-D oH DæMÎ ~ m[hDÌ[gL@ V IEEE 802.11e ñÎm[h c ਤ3 IEEE 802.11eରԠϧʔτΩϟογϡ TTL=3 TTL=2 TTL=1 TTL=0 AhzbNlbg[N ¶æ m[h M³ m[h ਤ4ϗοϓΛ3ʹ੍ݶͨ͠ྫ ैདྷͷϧʔτΩϟογϡͱͷҧ͍Λਤ3Ͱઆ໌͢Δɻܦ ࿏্ͷ͕ͯ͢IEEE 802.11eରԠϊʔυͰ͋Δܦ࿏͚ͩΛ Ωϟογϡ͍ͯ͠Δͷ͕ಛͰ͋Δɻ్தʹIEEE 802.11e ඇରԠϊʔυ͕͋Δ߹ɺͦͷܦ࿏Ωϟογϡͷର͔ Βআ֎͢ΔɻDSRϓϩτίϧͷैདྷͷϧʔτΩϟογϡͷ ֓೦Ͱɺ͜ͷܦ࿏هԱ͞Εͯ͠·͏ɻ͜ΕʹΑͬͯɺϦ ϯΫஅ࣌ͰޮΑ͘࠶ܦ࿏୳ࡧ͕Ͱ͖ɺ͔͠IEEE 802.11eʹରԠͨ͠༏ઌૹ৴Ͱͷ௨৴͕࠶։ՄೳͱͳΔɻ
ఏҊ͢ΔIEEE 802.11eରԠϧʔτΩϟογϡͰRREP ύέοτʹؚ·Ε͍ͯΔܦ࿏ͷΈΛهԱ͢ΔͷͰɺهԱҬͷ ແବগͳ͘ɺ͋Δఔ͕࣌ؒܦաͯ͠༗ޮͳܦ࿏ใ͕ ͍ͬͯΔՄೳੑ͕ߴ͍ɻ 2ɾ3 ϗοϓͷ੍ݶ DSRϓϩτίϧͰɺϗοϓͷ੍ݶಛʹنఆ͞Εͯ ͍ͳ͍ɻϗοϓͷେ͖͍ܦ࿏ɺ௨৴͕ෆ҆ఆʹͳΓ͕ͪ Ͱ͋Δɻ͔͠RREQύέοτΛ͍ൣғͰ֦ࢄͤͯ͞͠ ·͏ͨΊɺϗοϓͷ૿େͱͱʹΤϯυπʔΤϯυͷύ έοτૹ৴࣌ؒ৳ͼΔʹ͋Δɻ ͦ͜Ͱɺਤ4ͷΑ͏ʹIPϔομϑΟʔϧυͷTTL (Time To Live) ʹRREQύέοτͷసૹճΛه͠ɺRREQ ύέοτΛड͚औͬͨϊʔυ͕ͦΕΛॱʹݮࢉ͍͖ͯ͠ɺྵ ʹͳͬͨ࣌ͰɺRREQύέοτͷϒϩʔυΩϟετΛఀ ࢭ͢Δ͜ͱʹ͢Δɻ͜ΕͰϗοϓΛ੍ݶͰ͖Δɻ
3. IEEE 802.11e
ΞυϗοΫϞʔυͷ֦ு
ૹ৴ϊʔυ͕૿Ճ͢ΔͱɺEDCAΛར༻ͯ͠Ի·ͨϏ σΦΧςΰϦͷσʔλΛૹ৴͢ΔͱϑϨʔϜিಥ͕ى͖қ͘ ͳΔɻͦ͜Ͱ֤ϊʔυ͕ྡϊʔυͷΛѲ͠ɺEDCA ύϥϝʔλΛಈతʹมߋͰ͖ΔΑ͏IEEE 802.11eΞυϗο ΫϞʔυΛ֦ு͢Δ͜ͱΛఏҊ͢Δɻ * + ) t[ M t[ Tó t[ óM m[h+Í m[h)Æ ¼ÚÊM µÈÄàA m[h)̶ ݪª©é ਤ5ϑϨʔϜͷड৴ͱडͷྫ B C A C A B æ¾Ô T Ôã m[hAAh T m[hAAh T m[hBAh C A B T+Zàm[hðúÔ m[hB Ah T+t T+t T + t Ôã t ×Úm[hîñ X X X X ਤ6ϊʔυCͷྡϊʔυใͷߋ৽ঢ়گ ftHgÌ ftHgÌ `% &` # $` ! "`! ftHgÌ ftHgÌ ! `!' " ` m[h ä ftHg ~ ftHg ~ ! ftHg ~ " ftHg ~ # ftHg ~ $ ftHg ~e.g.) m = 4 if cn= 24 for node-n
ਤ7ίϯςϯγϣϯΟϯυͷόΠΞεm
3ɾ1 ϊʔυͷѲ
ΞΫηεΧςΰϦ͝ͱͷίϯςϯγϣϯΟϯυͷ্Լ ݶCWmax∗ [AC]ͱCWmin∗ [AC]ΛϊʔυʹΑͬͯมߋ
͢Δʹɺ֤ϊʔυ͕ྡ͢ΔϊʔυͷΛΔඞཁ͕͋ ΔɻແઢLANͰɺૹ৴ϊʔυ͕ड৴ϊʔυʹϑϨʔϜΛ ૹ৴͢ΔࡍɺࣗͷMACΞυϨεͱɺ૬खͷMACΞυϨ εΛϑϨʔϜʹՃͯ͠ૹ৴Λߦ͍ͬͯΔɻਤ5ʹࣔ͢Α͏ ʹɺૹ৴ϊʔυ͕ૹ৴ͨ͠ϑϨʔϜྡ͢Δͯ͢ͷϊʔ υ͕ड͍ͯ͠Δɻͦͯࣗ͠ͷMACΞυϨε͕डͨ͠ ϑϨʔϜʹؚ·Ε͍ͯΔ߹ʹ͚ͩɺͦͷϑϨʔϜΛऔΓࠐ ΉΑ͏ʹͳ͍ͬͯΔɻ ֤ϊʔυૹ৴ϊʔυͷૹ৴ϑϨʔϜΛड৴·ͨड͢ Δ͜ͱͰૹ৴ϊʔυͷMACΞυϨεΛࣝผͰ͖Δɻ 3ɾ2 EDCAύϥϝʔλͷಈతมߋ ਤ6ࠨͷΑ͏ʹɺϊʔυC͕ૹ৴ݩAͷMACΞυϨε Λडͨ͠ࡍɺϊʔυCͷྡϊʔυҰཡʹϊʔυAͷ MACΞυϨεͱͦͷऔಘ࣌ؒT͕ه͞ΕΔɻ֤ϊʔυʹ ݻ༗ͷηϧϊʔυղ์࣌ؒ(cell node release time)͕ ઃఆ͞Ε͓ͯΓɺਤ6ӈͷΑ͏ʹɺ͜ͷ࣌ؒΛܦաͨ͠ྡ ϊʔυใࣗಈతʹഁغ͞ΕΔ͜ͱʹͳΔɻ
MAC header Data FCS ACK One Cycle Data frame SIFS Next Data frame Wating time ਤ8εϧʔϓοτͷܭࢉϞσϧ busy Media Back-off time PIFS SIFS DIFS or Slot time AIFS[AC] Next Data frame Waiting time ਤ9ػ࣌ؒͷৄࡉϞσϧ ࠁͰͷྡϊʔυ(cn)͕ѲͰ͖Δɻ͜ͷcn Λ ͬͯίϯςϯγϣϯΟϯυͷόΠΞεmΛٻΊΔ ʢਤ7ࢀরʣɻ࠷ޙʹࣜ(1)∼(2)ʹΑͬͯΞΫηεΧςΰϦ ͝ͱʹίϯςϯγϣϯΟϯυͷ্ԼݶCWmin∗ [AC] ͱCWmax∗ [AC]Λಈతʹมߋ͢Δɻ CW∗
min[AC] = m · CWmin[AC] (1)
CW∗
max[AC] = m · CWmax[AC] (2)
͜͜ͰɺCWmin[AC]ͱCWmax[AC]ද1ʹ͋Δίϯς
ϯγϣϯΟϯυͷσϑΥϧτͰ͋Δɻίϯςϯγϣϯ Οϯυͷ্Լݶ࣍ষͷόοΫΦϑ࣌ؒͷܭࢉͰඞ ཁͱͳΔɻ͜ͷΑ͏ʹίϯςϯγϣϯΟϯυͷ্ԼݶΛ ಈతʹมߋ͢ΔΑ͏ʹ֦ுͨ͠ϓϩτίϧΛ͜͜Ͱ֦ு 802.11e (Extended 802.11e)ͱݺͿ͜ͱʹ͢Δɻ
4.
εϧʔϓοτͱϑϨʔϜিಥ
γϛϡϨʔγϣϯͰऔΓѻ͏ධՁࢦඪʹ͍ͭͯઆ໌͢Δɻ 4ɾ1 εϧʔϓοτ εϧʔϓοτ(throughput)ͱɺ୯Ґ࣌ؒͨΓͷσʔ λͷసૹͷ͜ͱͰ͋Δɻਤ8ʹDCFνϟωϧΞΫηε ͱEDCAνϟωϧΞΫηεͷεϧʔϓοτͷܭࢉϞσϧ 2) Λࣔ͢ɻIEEE 802.11ͷσʔλϑϨʔϜɺMACϔομɺ σʔλ෦͓ΑͼFCS (Frame Check Sequence)ؚ͕·ΕΔɻ ֤ϑϨʔϜͷσʔλαΠζΛද2্෦ʹࣔ͢ɻύϥϝʔλ จݙ 11)ʹج͍ͮͯઃఆ͍ͯ͠Δɻਤ8ͷதʹ͋Δػ ࣌ؒ(waiting time)ͷৄࡉϞσϧ͕ਤ9Ͱ͋ΔɻIEEE 802.11eͷ֤EDCAνϟωϧΞΫηεͷόοΫΦ ϑ࣌ؒ࣍ͷΑ͏ʹͯ͠ܭࢉ͞ΕΔɻॱΛͬͯઆ໌͢Δɻ ·ͣɺਤ9ʹ͋ΔϑϨʔϜִؒSIFS (Short Inter-Frame Space)ͱɺACK (Acknowledgement)ϑϨʔϜૹʹ༻ ͍ΒΕΔ࠷খ୯ҐͷϑϨʔϜִؒIFS (Inter-Frame Space) ͷ͜ͱͰ͋ΔɻεϩοτλΠϜ(Slot Time) ͱ௨৴Ͱ ͏Ұఆ࣌ؒͷ͜ͱͰ͋ΔɻϙʔϦϯά༻ϑϨʔϜִؒPIFS (Point Coordination Function Inter-Frame Space)ͱDCF
ද2εϧʔϓοτܭࢉϞσϧͷύϥϝʔλ
MAC header 24 octet Data size 1500 octet FCS size 4 octet ACK size 14 octet
DIFS 50 μs AIFS[AC BK] 140 μs AIFS[AC BE] 60 μs AIFS[AC VI] 40 μs AIFS[AC VO] 40 μs PIFS 30 μs Slot time 20 μs SIFS 10 μs νϟωϧΞΫηε༻ϑϨʔϜִؒDIFS (DCF Inter-Frame Space)࣍ࣜͷΑ͏ʹܭࢉ͞ΕΔɻ
P IF S = SIF S + SlotT ime (3)
DIF S = SIF S + SlotT ime × 2 (4) DIFSΛEDCAνϟωϧΞΫηε༻ʹ֦ுͨ֓͠೦͕ AIFS[AC]Ͱ͋ΔɻACΞΫηεΧςΰϦΛࣔ͢ɻAIFS ͱArbitration Inter-Frame SpaceͷུͰ͋ΔɻϑϨʔϜ ૹ৴·Ͱͷڧ੍ػ͕࣌ؒAIFS[AC]Ͱ͋Δͱଊ͑ͯΑ͍ɻ ද2Լ෦ʹࣔ͢Α͏ʹԻ(AC VO)ͱϏσΦ(AC VI)ͷ ϑϨʔϜૹ৴ִؒ2εϩοτλΠϜͱൺֱత͘ઃఆͯ͠ ͋ΔɻͦΕͰϑϨʔϜিಥى͜Δɻিಥ͕ىͬͨ͜ͱ͖ ʹόοΫΦϑ੍ޚΛߦ͏͕ɺͦ͜ͰඞཁͱͳΔͷ͕ࣜ(5)Ͱ ఆٛ͞ΕΔόοΫΦϑ࣌ؒ(back-off time) Ͱ͋Δɻিಥൃ ੜޙɺ͜ͷεϩοτλΠϜ͚ͩػ࣌ؒΛԆ͢ΔͷͰ͋ Δɻ͜ΕʹΑͬͯϑϨʔϜͷ࠶িಥΛݮͰ͖Δɻ όοΫΦϑ࣌ؒ=r × SlotT ime (5) ͜͜Ͱɺཚrr ∈ [0, CW ]ͷͰ͋Γɺίϯςϯγϣ ϯΟϯυ CW CWmin∗ [AC] ≤ CW ≤ CWmax∗ [AC] ͷൣғͷͰ͋ΔɻϑϨʔϜিಥૹΤϥʔ͕Ҿ͖ଓ͖ൃ ੜͨ͠߹ʹɺࣜ(6)ͰCW Λߋ৽͢Δɻ CW = (CW∗ min[AC] + 1) × 2n− 1, n :࠶ૹճ (6) ௨৴࣌ؒࣜ(7)ͷΑ͏ʹϑϨʔϜૹ৴࣌ؒͱػ࣌ؒͷ ߹ܭͰධՁ͢Δɻ͜͜ͰϑϨʔϜૹ৴࣌ؒࣜ(8)ͰҰҙʹ ධՁͰ͖Δɻ͔͠͠ػ࣌ؒʹ͍ͭͯɺDCFνϟωϧΞ Ϋηεͷ߹ࣜ(9)ͰɺEDCAνϟωϧΞΫηεͷ߹ ࣜ(10)ͰධՁ͢Δ͜ͱʹͳΔɻ ௨৴࣌ؒ=ϑϨʔϜૹ৴࣌ؒ+ػ࣌ؒ (7) ϑϨʔϜૹ৴࣌ؒ =σʔλϑϨʔϜαΠζ+ACKϑϨʔϜαΠζ ૹϨʔτ (8) ػ࣌ؒ=DIF S +όοΫΦϑ࣌ؒʢforDCFʣ (9) ػ࣌ؒ=AIF S[AC] +όοΫΦϑ࣌ؒʢforEDCAʣ (10)
εϧʔϓοτ୯Ґ࣌ؒͨΓͷૹ৴σʔλྔͰ͋Δ͔ Βɺ݁ہɺ࣍ࣜͷΑ͏ʹͯ͠ࢉग़Ͱ͖Δɻ εϧʔϓοτ=σʔλαΠζ ௨৴࣌ؒ (11) 4ɾ2 ϑϨʔϜিಥ DCFνϟωϧΞΫηεEDCAνϟωϧΞΫηεͷࡍ ʹɺෳͷૹ৴ϊʔυ͕ಉ࣌ʹϑϨʔϜΛૹ৴͢Δͱਖ਼͘͠ ड৴ϊʔυσʔλϑϨʔϜ͕ಧ͔ͳ͍ɻ͜ΕΛϑϨʔϜি ಥͱݺͿɻϑϨʔϜૹ৴ʹର͢ΔϑϨʔϜিಥͷׂ߹Λ ϑϨʔϜিಥ(frame collision rate)ͱͯ͠ఆٛ͢Δɻ
4ɾ3 ࠶ܦ࿏୳ࡧ࣌ؒͱ௨৴࠶։Ԇ࣌ؒ ࠶ܦ࿏୳ࡧ࣌ؒɺϦϯΫΕޙͷܦ࿏୳ࡧ࣌ؒͱܦ࿏Ԡ ࣌ؒͷͰࢉग़͢Δɻܦ࿏୳ࡧ࣌ؒͱɺૹ৴ݩϊʔυ͕ RREQύέοτΛϒϩʔυΩϟετ͠ɺதܧϊʔυΛܦͯɺ RREQύέοτ͕Ѽઌϊʔυʹ౸ண͢Δ·Ͱͷ࣌ؒΛ͍͏ɻ ܦ࿏Ԡ࣌ؒͱɺѼઌϊʔυ͕RREPύέοτΛૹ৴͠ ͯɺૹ৴ݩϊʔυ͕ͦΕΛड͚औΔ·Ͱͷ࣌ؒͰ͋Δɻ ௨৴࠶։Ԇ࣌ؒɺܦ࿏్தͰϊʔυফ໓ʹΑͬͯ࣍ ϗοϓૹ৴Ͱ͖ͳ͘ͳͬͨͱ͖ɺIEEE 802.11eରԠϧʔτ ΩϟογϡΛͬͯ௨৴͕࠶։͢Δ·Ͱͷ࣌ؒͱఆٛ͢Δɻ
5.
γϛϡϨʔγϣϯ݁Ռ͓Αͼߟ
ఏҊ๏ͷੑೳධՁΛߦ͏ͨΊɺJava 2 Standard Edition 1.4.2 ͰγϛϡϨʔλΛ։ൃ͠ɺPentium4 2.8GHz, 1GB RAMͰݕূΛߦͬͨɻ 5ɾ1 γϛϡϨʔγϣϯͷલఏ݅ͱఆڥ ϊʔυͯ͢IEEE 802.11eରԠϊʔυͱ͠ɺૹϨʔ τ54Mbpsͱ͢ΔɻIEEE 802.11eରԠϧʔτΩϟογϡ ʹอ࣋Ͱ͖Δܦ࿏64ͱͨ͠ɻ ૹ৴ݩϊʔυ1528ΦΫςοτͷσʔλϑϨʔϜΛόʔ ετతʹૹ৴͠ɺϊʔυؒͷεϧʔϓοτͷܭࢉʹࣜ(11) ΛجʹฏۉεϧʔϓοτͰධՁͨ͠ɻ୯ҐKbpsͰ͋Δɻ εϩοτλΠϜͳͲͷύϥϝʔλද2Λ༻ͨ͠ɻ ϊʔυΛਤ10ͷΑ͏ʹ150m×150mͷΦʔϓϯΤϦΞʹ ϥϯμϜʹஔ͠ɺΛ6ɺ14ɺ22ɺ30ɺ38 ʹͯ͠ݕূΛߦͬͨɻϊʔυؒํ௨৴ΛԾఆͨ͠ɻ 5ɾ2 શϊʔυಉҰνϟωϧΞΫηε࣌ͷੑೳධՁ ΤϦΞͷϊʔυ͕ද3ͷΑ͏ͳ௨৴ཁٻͰൃ৴ͨ͠ͱ͢ Δɻͭ·Γɺحϊʔυ͕1000ϛϦඵຖʹॱʹૹ৴ݩͱͳ ΓɺۮϊʔυΛѼઌͱͯ͠ૹ৴Λߦ͏ɻํ௨৴ΛԾఆ ͍ͯ͠ΔͷͰɺࠓѼઌϊʔυ͕ૹ৴ݩϊʔυͦͷ100 ϛϦޙʹ௨৴ཁٻΛൃ͢Δɻ͜ΕͰΤϯυπʔΤϯυͷ্Γ ͱԼΓ߹Θͤͯ2ຊͷ௨৴͕ൃੜ͢Δ͜ͱʹͳΔɻද3ͷΞ ΫηεΧςΰϦAC BEʢDCF૬ʣͰ͋Δ͕ɺAC VO ͓ΑͼAC VIʹ͍ͭͯಉ༷ͷ࣮ݧΛࢼΈͨɻ ϊʔυ1ʙϊʔυ6·ͰͷωοτϫʔΫͱϊʔυ1ʙϊʔ υ14·ͰͷωοτϫʔΫΛରʹɺ͜ΕΒ2ͭͷωοτ # "# " 1 27 38 12 !# 6 ! # 3 31 36 # 26 8 # 7 4 13 '# 24 20 ' &# 33 & 28 11 %# 5 9 17 % 2 $# $ 34 37 32 ## 25 # 22 16 10 "# 14 " !# 18 ! 35 # 19 21 # 15 23 29 30 # # # #! !#" "## ##$ $#% %#& &#' '# # # # ! !# " "# # ਤ10ϊʔυஔਤ ද3௨৴ཁٻҰཡ No. ૹ৴ݩ Ѽઌ ܦա࣌ؒ(ms) AC 1 1 2 1000 AC BE 2 2 1 1100 AC BE 3 3 4 2000 AC BE 4 4 3 2100 AC BE 5 5 6 3000 AC BE 6 6 5 3100 AC BE .. . ... ... ... ... 37 37 38 19000 AC BE 38 38 37 19100 AC BE ද4ฏۉܦ࿏୳ࡧ࣌ؒ ϓϩτίϧ ΞΫηεΧςΰϦ ฏۉܦ࿏୳ࡧ࣌ؒ ඪ४DSR DCF 2530.0ms
֦ுDSR EDCA (AC VO) 1167.1ms
ϫʔΫͰग़དྷ্͕ͬͨϦϯΫਤΛਤ11ͱਤ12ʹࣔ͢ɻ͜ ΕΒͷωοτϫʔΫΛߏங͢Δ·Ͱͷ1ܦ࿏ͨΓͷฏۉܦ ࿏୳ࡧ࣌ؒΛैདྷͷDSRϓϩτίϧͱఏҊ֦ͨ͠ுDSR ϓϩτίϧͰൺֱͯ͠Έͨɻ݁ՌΛද4ʹࣔ͢ɻDSRϓϩ τίϧͷ֦ுʹ͓͍ͯϗοϓΛ࠷େ3ʹݶఆ͍ͯ͠Δؔ ্ɺඪ४ͷDCFνϟωϧΞΫηεΛͬͨDSRϓϩτ ίϧΑΓఏҊ๏Ͱͷ࣌ؒͰܦ࿏୳ࡧ͕ऴ͍ྃͯ͠ Δɻ2ͭͷϦϯΫਤͰ֬ೝ͢Δͱɺ͔֬ʹϗοϓ࠷େ3 ·Ͱʹऩ·͍ͬͯΔ͜ͱ͕֬ೝͰ͖Δɻ
ఏҊ๏ͷ֦ு802.11e (Extended 802.11e)ͷνϟωϧΞ Ϋηεผͷฏۉεϧʔϓοτɺ38×2ຊͷશϦϯΫ͕͢ ͯಉҰΞΫηεΧςΰϦʹଐ͢ͷͰɺҰ֓ʹݴ͑ͳ͍ ͕ɺAC VO< AC BE < AC VIͷ͕ݟΒΕͨɻϏσ Φ(AC VI)ͱԻ(AC VO)ͷΞΫηεΧςΰϦʹ͍ͭͯɺ ैདྷͷIEEE 802.11eʢ͜ΕΛNormal802.11eͱॻ͘͜ͱʹ ͢ΔʣͱఏҊ๏ͷExtended802.11eΛฏۉεϧʔϓοτͰ
# "# " 1 !# 6 ! # 3 # # 4 '# ' &# & %# 5 % 2 $# $ ## # "# " !# ! # # # # # # ! !# " "# # ## $ $# % %# & &# ਤ11ϊʔυ6Ͱߏங͞ΕͨωοτϫʔΫͷϦϯΫਤ # "# " 1 12 !# 6 ! # 3 # 8 # 7 4 13 '# ' &# & 11 %# 5 9 % 2 $# $ ## # 10 "# 14 " !# ! # # # # # # ! !# " "# # ## $ $# % %# & &# ' '# # # ਤ12ϊʔυ14Ͱߏங͞ΕͨωοτϫʔΫͷϦϯΫਤ ൺֱͨ͠ͷ͕ਤ13ͱਤ14Ͱ͋Δɻ ϏσΦʹ͍ͭͯۇ͔Ͱ͋Δ͕ఏҊ๏ͷ༏ҐੑΛ֬ೝͰ ͖Δɻ͔͠͠Իʹ͍ͭͯͷ༏Ґੑ΄ͱΜͲ֬ೝͰ͖ͳ ͍ɻ͜ΕΛϑϨʔϜিಥͷ؍͔Βߟͯ͠ΈΔɻAC VI νϟωϧΞΫηεͷϑϨʔϜিಥΛਤ15ʹࣔ͠ɺAC VO νϟωϧΞΫηεͷͦΕΛਤ16ʹ·ͱΊͯΈͨɻԣ࣠ε ϧʔϓοτͷͱ͖ͱಉ༷ɺϊʔυͰ͋Δɻॎ࣠ࠓ ϑϨʔϜিಥͷฏۉͱͳ͍ͬͯΔɻϏσΦ(AC VI)Χς ΰϦͷিಥ͕ఏҊ๏Ͱ10%ఔվળ͞Ε͍ͯΔ͜ͱ ͕͔ΔɻҰํɺԻ(AC VO)ΧςΰϦͷিಥͷվળ෯ ͔ͳΓখ͍͞ɻ݁ہɺ͜ͷ͕ࠩεϧʔϓοτʹଟগͳΓͱ ӨڹΛ༩͍͑ͯΔͱղऍͰ͖Δɻ 0 200 400 600 800 1000 1200 1400 1600 1800 2000 4 6 8 10121416182022242628303234363840 Throughput (Kbps) Number of nodes
Extended 802.11e EDCA (AC-VI)
Normal 802.11e EDCA (AC-VI)
ਤ13 AC VIνϟωϧΞΫηεͷฏۉεϧʔϓοτ 0 200 400 600 800 1000 1200 1400 1600 1800 2000 4 6 8 10121416182022242628303234363840 Throughput (Kbps) Number of nodes
Extended 802.11e EDCA (AC-VO)
Normal 802.11e EDCA (AC-VO)
ਤ14 AC VOνϟωϧΞΫηεͷฏۉεϧʔϓοτ 15 20 25 30 35 40 45 4 6 8 10 1214 161820 2224 2628 303234 3638 40
Frame collision rate on AC_VI (%)
Number of nodes Extended 802.11e Normal 802.11e ਤ15 AC VIνϟωϧΞΫηεͷϑϨʔϜিಥ 5ɾ3 νϟωϧΞΫηεࠞࡏ࣌ͷੑೳධՁ ͜͜·ͰΞΫηεΧςΰϦ͕ͯ͢ಉҰͷ௨৴ཁٻͰ͋ Δ߹ͷݕূ݁ՌͰ͋ͬͨɻ͔͜͜ΒΞΫηεΧςΰϦ͕ ࠞࡏ͢Δ߹ʹ͍ͭͯݕূͯ͠ΈΔɻਤ13ͱਤ14ͷ݁Ռ Λࢀߟʹ࠷େ24·ͰͷϊʔυͰݕূͨ͠ɻϊʔυ ஔਤ10ͷ··Ͱɺϊʔυ25Ҏ߱Λແࢹ͢Δ͜ͱʹͳΔɻ
15 20 25 30 35 40 45 4 6 8 1012 1416 1820 2224 262830 3234 363840
Frame collision rate on AC_VO (%)
Number of nodes Extended 802.11e Normal 802.11e ਤ16 AC VOνϟωϧΞΫηεͷϑϨʔϜিಥ ද5ΞΫηεΧςΰϦࠞࡏ࣌ͷ௨৴ཁٻҰཡ No. ૹ৴ݩ Ѽઌ ܦա࣌ؒ(ms) AC 1 1 2 1000 AC BE 2 2 1 1100 AC BE 3 3 4 2000 AC VO 4 4 3 2100 AC VO 5 5 6 3000 AC VI 6 6 5 3100 AC VI 7 7 8 4000 AC BE 8 8 7 4100 AC BE 9 9 10 5000 AC VO 10 10 9 5100 AC VO 11 11 12 6000 AC VI 12 12 11 6100 AC VI 13 13 14 7000 AC BE 14 14 13 7100 AC BE 15 15 16 8000 AC VO 16 16 15 8100 AC VO 17 17 18 9000 AC VI 18 18 17 9100 AC VI 19 19 20 10000 AC BE 20 20 19 10100 AC BE 21 21 22 11000 AC VO 22 22 21 11100 AC VO 23 23 24 12000 AC VI 24 24 23 12100 AC VI
ΞΫηεΧςΰϦ(AC)͕ϕετΤϑΥʔτ(AC BE)ɺ Ի(AC VO)ɺϏσΦ(AC VI)ͳͲɺ͜ΕΒͷ௨৴ཁٻ͕ ಉҰΤϦΞʹࠞࡏ͢Δ߹Λఆ͢Δɻ௨৴ཁٻҰཡද5 ͷ௨ΓͰ͋ΔɻحϊʔυͱۮϊʔυϖΞʹͳ͓ͬͯΓ ํͰ௨৴͢ΔͱԾఆ͍ͯ͠Δɻૹ৴ݩɺѼઌɺܦա࣌ؒ ͷҙຯද3ͱಉ͡Ͱ͋Δɻ ϊʔυ1͔Βϊʔυ24·Ͱ͕ॱ࣍ɺ௨৴Λ։࢝͢Δɻॱ ࣍ೖ͞Εͨͱ͖ͷฏۉεϧʔϓοτਤ17ͷΑ͏ʹͳͬ ͨɻ͜ͷਤఏҊ๏Ͱ͋Δ֦ு802.11eͷEDCAνϟωϧ ΞΫηεͷ݁ՌͰ͋Δɻεϧʔϓοτʹண͢Εɺ֓Ͷ AC BE< AC VI < AC VOͷ݁Ռʹͳ͍ͬͯΔɻϊʔυ 13ͱϊʔυ14͕௨৴Λ࢝Ίͨͱ͜ΖͰɺฏۉεϧʔϓοτ ͕AC BE> AC VIͱٯస͍ͯ͠Δɻͭ·ΓΞΫηεΧς ΰϦࠞࡏ࣌ʹ߆ΒͣɺԻͰଳҬ֬อͰ͖͍ͯͳ͍͜ͱʹ 0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 0 2 4 6 8 10 12 14 16 18 20 22 24 Throughput (Kbps) Number of nodes
Extended 802.11e EDCA (AC-BE)
Extended 802.11e EDCA (AC-VO)
Extended 802.11e EDCA (AC-VI )
ਤ17νϟωϧΞΫηεࠞࡏ࣌ͷฏۉεϧʔϓοτ ͳΔɻ͜ΕҎԼͷΑ͏ͳཧ༝Ͱ͋Ζ͏ͱਪ͞ΕΔɻ No.12·Ͱͷ௨৴ܦ࿏͕֬อ͞Εͨ࣌ͰAC BEͷ௨ ৴ܦ࿏4ͭɺAC VOͷܦ࿏4ͭɺAC VIͷܦ࿏4 ͭଘࡏ͢Δɻ͜ͷஈ֊Ͱεϧʔϓοτ͔ͳΓམ͍ͪͯΔɻ ͜͜ʹAC BEΞΫηεΧςΰϦͷ௨৴No.13ͱNo.14͕ ৽ͨʹ2ׂͭΓࠐΜͰ͘Δɻ݁ՌɺAC VOͱAC VIͷε ϧʔϓοτ͕͞ΒʹམͪࠐΉɻམͪࠐΜͩ࣌ͰAC BE> AC VIͷٯసݱ͕ىͬͨ͜ɻͦͷޙɺNo.15ͱNo.16ͷ AC VOΞΫηεΧςΰϦͷ௨৴͕࢝·Δ͕ɺ֦ு802.11e ͷEDCAνϟωϧΞΫηεͰԻ(AC VO)ͱϏσΦ (AC VI)͕༏ઌ͞ΕΔͷͰɺϊʔυ15ͱϊʔυ16͕௨৴ Λ։࢝ͨ࣌͠ͰͦΕΒͷεϧʔϓοτগ্͕͠Δ͜ͱʹ ͳΔɻҎ্ͷ܁Γฦ͠ͱߟ͑Εɺਤ17ͷઢ֓Ͷਖ਼ ͍͠ͱཧղͰ͖Δɻ 5ɾ4 IEEE 802.11eରԠϧʔτΩϟογϡͷ༗ޮੑ ఏҊͨ͠IEEE 802.11eରԠϧʔτΩϟογϡͷݕূ ߦͬͨɻද5ͷ௨৴ཁٻ͕͋ͬͨͱͯ͠ɺγϛϡϨʔγϣϯ ։͔࢝Β12ඵޙʹϊʔυ4·ͨϊʔυ8Λڧ੍తʹফ໓ ͤ͞Δ࣮ݧΛͨ͠ɻ2ͭΛಉ࣌ʹফ໓ͤͨ͞Θ͚Ͱͳ͍ɻ ϊʔυফ໓ͷ͔࣌ΒIEEE 802.11eରԠϧʔτΩϟογϡ ใΛ༻͍ͯ௨৴࠶։·Ͱͷॴཁ࣌ؒΛܭଌͨ͠ɻ ·ͣ࠷ॳͷ࣮ݧͰɺ24ʢϊʔυ1ʙϊʔυ24ʣͷ͏ ͪɺϊʔυ4͕ফ໓ͨ࣌͠Ͱϊʔυ3ͱͷ௨৴్͕ઈ͑Δ ͷવͰ͋Δɻ͜ΕҎ֎ʹɺϊʔυ1ˠϊʔυ3ˠϊʔ υ4ˠϊʔυ2ͱ͍͏ܦ࿏Ͱσʔλ͕ૹ৴͞Ε͍ͯͨɻϊʔ υ4ͷফ໓ʹΑΓɺϊʔυ3͕ϊʔυ4ϑϨʔϜΛૹ৴ Ͱ͖ͳ͍ঢ়گ͕ൃੜͨ͠ɻͦ͜Ͱϊʔυ3͕อ࣋͢Δϧʔ τΩϟογϡใΛͬͯɺϊʔυ11Λհ͠ϊʔυ2ϑ ϨʔϜΛૹ৴͢Δܦ࿏Λཱ֬ͯ͠ɺ௨৴Λ࠶։͍ͯͨ͠ɻ͜ ͷঢ়گΛࣔ͢ͷ͕ਤ18Ͱ͋Δɻ݁Ռɺ࠶ܦ࿏୳ࡧΛߦΘͣɺ 380.4msͷ௨৴࠶։Ԇ࣌ؒͷΈͰ௨৴Λ࠶։Ͱ͖͍ͯͨɻ ࣍ͷ࣮ݧͰɺϊʔυ4Ͱͳ͘ϊʔυ8Λڧ੍తʹফ໓ ͤͨ͞ɻࠓਤ19ͷΑ͏ʹܦ࿏Λมߋ͍ͯͨ͠ɻΓ ࠶ܦ࿏୳ࡧΛߦΘͣɺ57.1msͷ௨৴࠶։Ԇ࣌ؒͷΈͰ௨ ৴Λ࠶։͍ͯͨ͜͠ͱΛ֬ೝͨ͠ɻද4ʹࣔͨ͠ฏۉܦ࿏୳
# "# " 27 38 12 !# 6 ! # 3 31 36 # 26 8 # 7 4 13 '# 24 20 ' &# 33 & 28 11 %# 5 9 17 % 2 $# $ 34 37 32 ## 25 # 22 16 10 1 # # #! !#" "## ##$ $#% %#& &#' '# # # # ! !# " "# # ਤ18ϊʔυ4ফ໓ʹΑΔܦ࿏มߋ # "# " 27 38 12 !# 6 ! # 3 31 36 # 26 8 # 7 4 13 '# 24 20 ' &# 33 & 28 11 %# 5 9 17 % 2 $# $ 34 37 32 ## 25 # 22 16 10 1 # # #! !#" "## ##$ $#% %#& &#' '# # # # ! !# " "# # ਤ19ϊʔυ8ফ໓ʹΑΔܦ࿏มߋ ࡧ࣌ؒʹൺΕɺඇৗʹ͍࣌ؒͰ௨৴ͷ࠶։ʹޭͯ͠ ͍Δͱ͍͑Δɻ
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·ͣɺDSRϓϩτίϧʹؔ͢Δ3ͭͷ֦ுΛఏҊͨ͠ɻ ୈ1ʹɺΦϓγϣϯྖҬΛར༻ͨ͠IEEE 802.11eΞΫηε ΧςΰϦͷରԠɻୈ2ʹɺRREPύέοτʹΑΔIEEE 802.11ରԠϧʔτΩϟογϡͷํ๏ɺୈ3ʹϗοϓ੍ݶʹ ΑΔωοτϫʔΫͷ҆ఆԽͰ͋Δɻ͞ΒʹɺIEEE 802.11e ΞυϗοΫϞʔυͷ֦ுͱͯ͠EDCAύϥϝʔλͷಈతม ߋํ๏ʹ͍ͭͯఏҊͨ͠ɻ Java2 SE 1.4.2ͰγϛϡϨʔλΛ։ൃ͠ɺεϧʔϓοτɺ ϑϨʔϜিಥɺͦͯ͠ܦ࿏୳ࡧ࣌ؒͱ͍ͬͨఆྔతධՁࢦ ඪΛ༻͍ͯఏҊ๏ͷ༗ޮੑΛݕূͨ͠ɻϑϨʔϜিಥʹͭ ͍ͯఏҊ๏Ͱ%͔Β10%ఔΛݮগͤ͞Δ͜ͱʹޭ ͨ͠ɻεϧʔϓοτʹ͍ͭͯݦஶͳվળʹࢸΒͳ͔ͬ ͨɻ͜ͷ݁ՌΑΓɺݱߦͷIEEE 802.11eͷίϯςϯγϣϯ ΟϯυͰेػೳ͓ͯ͠Γɺྡ͢ΔϊʔυΛߟྀ ͯͦ͠ͷ্ԼݶΛಈతʹมߋͨ͠ͱͯ͠ɺεϧʔϓοτ ্ͷతد༩গͳ͍ͱਪଌ͞ΕΔɻ ಉҰΤϦΞʹ20Ҏ্ͷϊʔυ͕ଘࡏ͢ΔͱɺͲͷΞΫ ηεΧςΰϦͰҰఆଳҬͷ௨৴֬อ͕ࠔͰ͋Δ͜ͱ͕࣮ ݧ͔Β֬ೝͰ͖ͨɻ͜ͷղܾʹ੍ޚύέοτσʔλύ έοτΛ੍͢Δ৽ͨͳΈ͕ඞཁͰ͋Ζ͏ɻँ ࣙ
ຊݚڀΛߦ͢Δʹ͋ͨΓɺฏ18ຊֶେֶӃੜ࢈γ εςϜֶઐ߈मྃͷேډ໌ࢯʢݱࡏ ຊΠϯγϡϨʔ γϣϯגࣜձࣾ ۈʣʹଟେͳڠྗΛಘͨɻ͜͜ʹँҙ Λද͢Δɻࢀߟจݙ
1) Mihaela Cardei, Ionut Cardei, and Ding-Zhu Du: Resource Management in Wireless Networking, Springer, 2005.
2) कਖ਼ത,ٱอాप࣏: վగ൛802.11ߴແઢLANڭ Պॻ,ΠϯϓϨε, 2005.
3) IEEE Std. 802.11e-2005, Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specification, Amendment 8: Medium Access Control (MAC) Quality of Service Enhancements, November 2005.
4) Yang Xiao: “IEEE 802.11e: QoS Provisioning at the MAC Layer”, IEEE Wireless Communications, Vol. 11, No. 3, pp. 72–79, June 2004.
5) David B. Johnson, David A. Maltz, and Yih-Chun Hu: The Dynamic Source Routing Protocol for Mo-bile Ad Hoc Networks (DSR)ʡ, IETF MANET Work-ing Group Internet-Draft, July 2004.
6) Ali Hamidian and Ulf K¨orner: “An enhancement to the IEEE 802.11e EDCA providing QoS guaran-tees”, Telecommunication Systems - Modeling, Anal-ysis, Design and Management, Vol. 31, No. 2-3, pp. 195–212, 2006.
7) Yi-Wen Lan, Jui-Hung Yeh, Jyh-Cheng Chen, and Zi-Tsan Chou: “Performance Enhancement of IEEE 802.11e EDCA by Contention Adaption”, 2005 IEEE 61st Vehicular Technology Conference, VTC2005-Spring, Vol. 3, pp. 2096–2100, 2005.
8) Luca Vollero, Albert Banchs, and Giulio Iannello: “ACKS: A Technique to Reduce the Impact of Legacy Stations in 802.11e EDCA WLANs”, IEEE Commu-nications Letters, Vol. 9, No. 4, pp. 346–348, April 2005.
9) ՏଜݑҰ, Ҫ্อ, খּݪक, ൧௩ਖ਼: “ެऺແઢ LAN༻IEEE 802.11eରԠجہʹ͓͚ΔEDCAύ ϥϝʔλಈతߋ৽ػೳͷ։ൃ”,ిࢠใ௨৴ֶձ2005 ιαΠΤςΟେձߨԋจू, B-5-183, p. 583, 2005. 10) ҏ౻խ,ேډ໌: “QoS੍ޚΛߟྀͨ͠DSRϓϩτί ϧͷ֦ு”, FIT2006ୈ5ճใՊֶٕज़ϑΥʔϥϜ Ұ ൠߨԋจू ୈ4, No. L-074, pp. 179–180, 2006. 11) দߐӳ໌,कਖ਼ത,ࠤ౻໌༤,ลೋ: ߴϫΠϠϨ εΞΫηεٕज़,ిࢠใ௨৴ֶձ, 2004. ʢडཧ ฏ213݄19ʣ
