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Link Quality Analysis of mobile 802.11n

B671801b688016898718badee0abbf0f?s=47 Yongsen Ma
October 21, 2012

Link Quality Analysis of mobile 802.11n

Weekly Meeting of 2012.08.09

B671801b688016898718badee0abbf0f?s=128

Yongsen Ma

October 21, 2012
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  1. µ0 3‚ï 5Uµ £Ä802.11n äó´Ÿþ©Û 3‚ÿÁ!ï †ýÿ ê [Ü September

    18, 2012 ê [Ü £Ä802.11n äó´Ÿþ©Û
  2. µ0 3‚ï 5Uµ Jj 1 µ0 802.11n IO9A^ 802.11n #Eâ

    ¯K9ƒ'óŠ 2 3‚ï ÿÁ•{ PDR-RSSï „Ç· Ž{ 3 5Uµ ÿÁŽ{µ óéþµ ê [Ü £Ä802.11n äó´Ÿþ©Û
  3. µ0 3‚ï 5Uµ 802.11n IO9A^ 802.11n #Eâ ¯K9ƒ'óŠ Jj 1

    µ0 802.11n IO9A^ 802.11n #Eâ ¯K9ƒ'óŠ 2 3‚ï ÿÁ•{ PDR-RSSï „Ç· Ž{ 3 5Uµ ÿÁŽ{µ óéþµ ê [Ü £Ä802.11n äó´Ÿþ©Û
  4. µ0 3‚ï 5Uµ 802.11n IO9A^ 802.11n #Eâ ¯K9ƒ'óŠ 802.11IOuІA^ •

    IEEE 802.11´Ã‚Û• (WLAN) ÆI O§l1997c1˜g ªuÙ y3˜†kX 2• A^§'X1999c¤á Wi-Fié†" • l•Ð 802.11 ©IO(2M,2.4G) 5 802.11a(54M,5G)Ú802.11g(54M,2.4G)§2 802.11n(150M/stream,2.4/5G)§802.11‡N ÂÏ&Eâ •#?Ð" • 59% {I¤c<ÏL)P Wi-Fi½Ã Åþ §•,LTE!WiMax!4G Eâ•3¯ „uЧ802.11E,¬Ók˜½° §'X8 cïÄ õ 802.11sÚ802.11p§±9m©Ý \A^ 802.11acÚ802.11ad" ê [Ü £Ä802.11n äó´Ÿþ©Û
  5. µ0 3‚ï 5Uµ 802.11n IO9A^ 802.11n #Eâ ¯K9ƒ'óŠ Jj 1

    µ0 802.11n IO9A^ 802.11n #Eâ ¯K9ƒ'óŠ 2 3‚ï ÿÁ•{ PDR-RSSï „Ç· Ž{ 3 5Uµ ÿÁŽ{µ óéþµ ê [Ü £Ä802.11n äó´Ÿþ©Û
  6. µ0 3‚ï 5Uµ 802.11n IO9A^ 802.11n #Eâ ¯K9ƒ'óŠ 802.11n PHY/MAC#Eâ

    PHY Eâ MIMOµæ^õU‚9˜mE^Eâ§J,PHYóéþ9C X‰Œ§ÓžJpXÚ-½5¶ HT20/HT40µæ^(¹& E⧕Ð/)û1Å f! Ûõ/ ³ªà ¯K" MAC Eâ A-MPDUµvàÜEâ=õ‡v ^˜‡MACÞܧӞ ü$ACKuxªÇ§ü$ux/ Âm•§JpDÑ Ç¶ SGIµ400ns om…§ü$žmm•§JpMACóéþ" 802.11næ^PHYÚMAC ˆ‘#Eâ§l y•p óéþ†CX‰Œ" ê [Ü £Ä802.11n äó´Ÿþ©Û
  7. µ0 3‚ï 5Uµ 802.11n IO9A^ 802.11n #Eâ ¯K9ƒ'óŠ Jj 1

    µ0 802.11n IO9A^ 802.11n #Eâ ¯K9ƒ'óŠ 2 3‚ï ÿÁ•{ PDR-RSSï „Ç· Ž{ 3 5Uµ ÿÁŽ{µ óéþµ ê [Ü £Ä802.11n äó´Ÿþ©Û
  8. µ0 3‚ï 5Uµ 802.11n IO9A^ 802.11n #Eâ ¯K9ƒ'óŠ 802.11n äÿÁ†

    ˜ 802.11n PHY/MAC#E⦠äÿÁ† ˜••E, DÚ Ã‚ ä ˜½ÄuÌÄ&ÿ§½Äu ½PDR-RSS .§3802.11n ä¥Ã{÷võ« ˜9pDÑ„Ç ‡¦" Xã1c¤«§3¤k ÀJ HT/GI/MCS ˜¥§Œ 34%á \LÞI•¥§$–k8% ˜¦ PDR<10%§ù«œ¹3 £Ä802.11n 䥕•²w" PDR-RSS Model PDR RSS Model Measure Rate Adaption TX RX Probe Predict Database Channel Access Power Control Routing PHY/MAC Settings Application (a) 0 20 40 60 80 100 -90 -80 -70 -60 -50 -40 PDR(%) RSS(dBm) δ- δ+ HT20/LGI MCS 8 MCS 10 MCS 12 MCS 14 (b) 0 0 0 0 -90 -80 -70 -60 -50 -40 -30 -20 HT/GI/MCS RSS(dBm) HT20/LGI HT20/SGI HT40/LGI HT40/SGI 15 15 15 15 transition window selected MCS (c) ê [Ü £Ä802.11n äó´Ÿþ©Û
  9. µ0 3‚ï 5Uµ 802.11n IO9A^ 802.11n #Eâ ¯K9ƒ'óŠ ¯K Ï

    ó´Ÿþ ˜m-žmõ 59 ä ˜ õ 5 1 · ÿÁ•{Ã{·Aó´Ÿþ ˜m-žmCz§3 p DфdžPDR]žü$ž§¦ ÿÁ(J p¶ 2 õ ˜O\ÿÁ†ÀJE,5§ØÓ ˜ LÞI•5ŸØ Ó§éuÌÄ&ÿÚ ½ .§Ñ¬O\¢– E,Ý" -100 -80 -60 -40 -20 0 0 20 40 60 80 100 RSS(dBm) LOS NLOS -85 -80 -75 0 20 40 60 80 100 0 20 40 60 80 100 PDR(%) Time(s) (a) 0 0.2 0.4 0.6 0.8 1 -90 -60 -30 0 CDF RSS(dBm) T2, r4 T2, r5 T2, r6 (b) 20 40 60 80 100 0 1 2 3 PDR(%) Time(s) static Δt=10ms Δt=50ms Δt=100ms (c) ê [Ü £Ä802.11n äó´Ÿþ©Û
  10. µ0 3‚ï 5Uµ 802.11n IO9A^ 802.11n #Eâ ¯K9ƒ'óŠ )û•Yµ3‚PDR-RSSï µe

    •I© ÿÁµDSWA Ôn µRSS/SNR/SINR/CSI ó´ µDѤõÇ(PDR) 3‚¢ÿ .µGradedM Ôn µMIMO§HT20/HT40 ó´ µLGI/SGI þ ] © µGradedR APsµ& \!ªÌ+n STAsµ„Ç››!´dÀJ Database PDR-RSS Model PDR RSS HT-GI-MCS Index Model Application Measure GradedM GradedR DSWA HT-GI-MCS Channel Access Power Control Routing Rate Adaption TX RX Update PHY/MAC Settings 1 éó´Ÿþ˜m-žm9 ˜õ 5§æ^Ä wÄI•²þ§J pÿÁ°Ý¶ 2 æ^3‚ÿÁ†ï •ª§O( •x c ˜e äG §•þ A^JøŒ‚&E¶ 3 (ÜÄ ÿÁ†3‚ï §Jp„ Ç· Ç" ê [Ü £Ä802.11n äó´Ÿþ©Û
  11. µ0 3‚ï 5Uµ ÿÁ•{ PDR-RSSï „Ç· Ž{ Jj 1 µ0

    802.11n IO9A^ 802.11n #Eâ ¯K9ƒ'óŠ 2 3‚ï ÿÁ•{ PDR-RSSï „Ç· Ž{ 3 5Uµ ÿÁŽ{µ óéþµ ê [Ü £Ä802.11n äó´Ÿþ©Û
  12. µ0 3‚ï 5Uµ ÿÁ•{ PDR-RSSï „Ç· Ž{ DѤõÇÿÁ . éuz‡uxêâ•i(i

    = 1, 2, 3...)§Ù ÂG xi Œ±½Â •lÑ‘ÅL§§dxi = {0, 1}L«§Ù¥xi = 1L«1i‡ ê╤õ Â" z˜‡uxê╠¤õVÇ•P(xi = 1) = pi §Œ± dSINR .5•x§½öÄu¢ÿêâ PDR-RSS ." pi = Prob[SINRi(t) > δ] = Prob[ Ri(t) Ii(t) + n > δ] (1) Ù¥SINRi(t) •&D', δ•SINR€•Š§Ri(t)• Â&Ò rݧIi(t)•&ÒZ6§n• µD(§˜„• ½Š" ê [Ü £Ä802.11n äó´Ÿþ©Û
  13. µ0 3‚ï 5Uµ ÿÁ•{ PDR-RSSï „Ç· Ž{ DѤõÇÿÁ . 3·

     䥧Œ±@•SINR½RSS3 ážmS ±ØC§Ïd٠ɤõVÇŒ±w‰~ê§xi •ÕáÓ© ÙCþ…kP(xi = 1) = pi = p§džS {xi}{z•Ëã| L§" 3£Ä 䥧du!: £Ä59Ù‘5 õ» A§\þ ä ˜ É5§¦ äG äk²w žCA:§Ny3ÿÁ .þB´ ¤õVÇpi ‘Xi ØÓ Cz" ê [Ü £Ä802.11n äó´Ÿþ©Û
  14. µ0 3‚ï 5Uµ ÿÁ•{ PDR-RSSï „Ç· Ž{ · äPDRÿÁ•{ EWMA:

    ˆ Pw [k] = α ˆ Pw [k − 1] + (1 − α)P[k] 1 EWMA \ ÏfαéÿÁ°ÝkéŒK•§3¢SÿÁL §¥§\ Ïf˜„30.1 0.4ƒm?1À " ½ αŠ ¦ ÿÁ°(ÝN´É .‚¸† ä ˜Cz K•¶ 2 EWMA I••ÝÓ K•ÿÁ°Ý§· ä¥I•• ݘ„• ½Š(100ms½50ms)§ ä$13pDÑ„ Çž§EWMA¬¢¦KPDR ]žeü" 0 1 xi Last Window W; P[k-1] Current Window W; P[k] ê [Ü £Ä802.11n äó´Ÿþ©Û
  15. µ0 3‚ï 5Uµ ÿÁ•{ PDR-RSSï „Ç· Ž{ £Ä äPDRÿÁ•{ DSWA:

    ˆ Ps[k] = βP [k] + (1 − β)P[k] £Ä802.11n ä¥ PDRÿþ§Q‡·A‚¸CzE¤ ä G ]žÅħq‡÷võ« ˜ÀJ ‡¦" 1 ÏLwÄÏfβÀ þ˜gOŽ¥‚C cž• Ü©ê â§ü$PDR ]žCzéÿÁ(J K•¶ 2 I••ÝW•¯‡°Ä…† ä ˜Ã'§ ´Šâ c äG Cz§éÿÁ°Ý†m•?1²ï" 0 1 xi Last Window W(k-1,n) ; P[k-1] Current Window (1-β(k,n) )W(k,n) ; P[k] xi = 0 xi = 1 β(k,n) W(k,n) ; P'[k] Sliding Window ê [Ü £Ä802.11n äó´Ÿþ©Û
  16. µ0 3‚ï 5Uµ ÿÁ•{ PDR-RSSï „Ç· Ž{ £Ä äPDRÿÁ•{ DSWA:

    ˆ Ps[k] = βP [k] + (1 − β)P[k] 0 1 xi Last Window W(k-1,n) ; P[k-1] Current Window (1-β(k,n) )W(k,n) ; P[k] xi = 0 xi = 1 β(k,n) W(k,n) ; P'[k] Sliding Window W(k,n) = n i=1 ωi γi ηi n i=1 ωi (2) β(k,n) = 1 + n i=1 ωi γi n i=1 ωi (3) Ù¥γi •PDRCzÏfµ γi = 1+P[k −n+i]−P[k −n+i −1], 1 ≤ i ≤ n, ωi •\ Ïfµ ωi = 1 2 n−i 2 , 1 ≤ i ≤ n ê [Ü £Ä802.11n äó´Ÿþ©Û
  17. µ0 3‚ï 5Uµ ÿÁ•{ PDR-RSSï „Ç· Ž{ Jj 1 µ0

    802.11n IO9A^ 802.11n #Eâ ¯K9ƒ'óŠ 2 3‚ï ÿÁ•{ PDR-RSSï „Ç· Ž{ 3 5Uµ ÿÁŽ{µ óéþµ ê [Ü £Ä802.11n äó´Ÿþ©Û
  18. µ0 3‚ï 5Uµ ÿÁ•{ PDR-RSSï „Ç· Ž{ PDR-RSS .•x 1

    & a.(HT20/HT40)µHT40•N´É‚¸CzK•§ƒ Óœ¹e٠€••p§…LÞI••Ý••¶ 2 DÑ„Ç(MCS)µ €•‘XDÑ„Ç Jp OŒ§ MCSpu14žI••ÝŒu10dB¶ 3 om…(LGI/SGI)µ3 $„ÇžÄ vk«O§ MCS pu14žSGIŒ±²wJ,PDR§cÙéuHT40& " 0 10 20 30 40 50 60 70 80 90 100 -90 -80 -70 -60 -50 -40 -30 -20 PDR(%) RSS(dBm) HT20/SGI MCS 8 MCS 10 MCS 12 MCS 14 0 10 20 30 40 50 60 70 80 90 100 -90 -80 -70 -60 -50 -40 -30 -20 -10 RSS(dBm) HT40/SGI MCS 8 MCS 10 MCS 12 MCS 14 (a) GI = 400ns 0 10 20 30 40 50 60 70 80 90 100 -90 -80 -70 -60 -50 -40 -30 -20 PDR(%) RSS(dBm) HT20/LGI MCS 8 MCS 10 MCS 12 MCS 14 0 10 20 30 40 50 60 70 80 90 100 -90 -80 -70 -60 -50 -40 -30 -20 -10 RSS(dBm) HT40/LGI MCS 8 MCS 10 MCS 12 MCS 14 (b) GI = 800ns 0 10 20 30 40 50 60 70 80 90 100 -90 -80 -70 -60 -50 -40 -30 -20 PDR(%) RSS(dBm) HT20/MCS15 SGI LGI 0 10 20 30 40 50 60 70 80 90 100 -90 -80 -70 -60 -50 -40 -30 -20 -10 RSS(dBm) HT40/MCS15 SGI LGI (c) MCS 15 ê [Ü £Ä802.11n äó´Ÿþ©Û
  19. µ0 3‚ï 5Uµ ÿÁ•{ PDR-RSSï „Ç· Ž{ 3‚PDR-RSSï Ž{ ÏLЩz¼

    © PDR-RSS .§ ¿;•uGradedT¥§ ëêu)Cz ž?13‚•#§éGradedT?1üS ¼ HT/GI/MCS¢Ú" T¢Ú‡A ¤k ˜3 cG eŒ ¼ 5U§Œ±Š•PHY/MACëêJ ø‰þ A^" c ˜ePDR<90%½RSS< δ+ §½ öPDRÚRSS±Y-½§ Ã{÷v„ ÇI¦§Šâht-gi-mcs-table-#ÀJÜ · ˜" ê [Ü £Ä802.11n äó´Ÿþ©Û
  20. µ0 3‚ï 5Uµ ÿÁ•{ PDR-RSSï „Ç· Ž{ Jj 1 µ0

    802.11n IO9A^ 802.11n #Eâ ¯K9ƒ'óŠ 2 3‚ï ÿÁ•{ PDR-RSSï „Ç· Ž{ 3 5Uµ ÿÁŽ{µ óéþµ ê [Ü £Ä802.11n äó´Ÿþ©Û
  21. µ0 3‚ï 5Uµ ÿÁ•{ PDR-RSSï „Ç· Ž{ Ž{ O†¢y DѤõÇ•I

    ÏLath9kNÁ8¹e ÚOêâ?1OŽµ ”/sys/kernel/debug/ieee80211/phy0/ath9k/rcstat” ”/sys/kernel/debug/ieee80211/phy0/ath9k/xmit” ”/sys/kernel/debug/ieee80211/phy0/ath9k/recv” Wireless device Linux kernel xmit.c rc.c recv.c tx rx ath9k nl80211 cfg80211 mac80211 ieee80211 P(.) Ra (.) Rc (.) D(.) G(.) D(.): DSWA G(.): Graded Model P(.): Packet Delivery Rc (.): Rate Control Ra (.): RSS Average W,β PDR RSS η,γ [δ- ,δ+ ] Network Layer Device Layer DSWA.c GradedM.c ê [Ü £Ä802.11n äó´Ÿþ©Û
  22. µ0 3‚ï 5Uµ ÿÁŽ{µ óéþµ Jj 1 µ0 802.11n IO9A^

    802.11n #Eâ ¯K9ƒ'óŠ 2 3‚ï ÿÁ•{ PDR-RSSï „Ç· Ž{ 3 5Uµ ÿÁŽ{µ óéþµ ê [Ü £Ä802.11n äó´Ÿþ©Û
  23. µ0 3‚ï 5Uµ ÿÁŽ{µ óéþµ ÿÁ°Ý9m•µ DSWAÿþØ µ E[∆PDRs[k +

    1]] = E[βP [k] + (1 − β)P[k + 1] − pn ] = βE[P [k]] + (1 − β)E[P[k + 1]] − pn = βp [k] + (1 − β)p[k + 1] − pn (4) D[∆PDRs[k + 1]] = D[βP [k] + (1 − β)P[k + 1] − pn ] = β2D[P [k]] + (1 − β)2D[P[k + 1]] = β2q [k] + (1 − β)2q[k + 1] (5) Ù¥pn = p(k+1)W−kT •O(Š§p [k]!p[k]Úq [k]!q[k]©Oé Aupi †pi(1 − pi)31kgOŽ±ÏS OŠ ê [Ü £Ä802.11n äó´Ÿþ©Û
  24. µ0 3‚ï 5Uµ ÿÁŽ{µ óéþµ ÿÁ°Ý9m•µ \ Ž{†wÄŽ{ÿÁØ é' 0

    200 400 600 800 1000 0.0 0.2 0.4 0.6 0.8 1.0 Pacekts Transmitted Packets Received Probability (a) ÂVÇ Packet Delivery Ratio Measurement Error 0 10 20 30 40 50 0.4 0.2 0.0 0.2 0.4 0.6 0.8 1.0 Compute Cycles (b) \ Ž{(α = 0.5) Measurement Error Packet Delivery Ratio 0 10 20 30 40 50 60 70 0.4 0.2 0.0 0.2 0.4 0.6 0.8 1.0 Compute Cycles (c) wÄŽ{(β = 0.3) 3ƒÓ^‡e§wÄŽ{ƒéu\ Ž{äk•p ž 5§Ó žÙÿÁØ •$"wÄŽ{ ÿÁØ ˜„$u0.010§… β = 0.3ž§ÙØ $u0.001§ \ Ž{ ÿÁØ 30.019 0.032ƒm" ê [Ü £Ä802.11n äó´Ÿþ©Û
  25. µ0 3‚ï 5Uµ ÿÁŽ{µ óéþµ ÿÁŽ{°Ý9m•µ oN ÿÁØ •¡§DSWA²w$uEWMA¶l\ȩټꌱwѧEWMAÿþ Š–•pu¢SŠ¶DSWA

    I••Ý•‹ äG k'§†DÑ„ÇÃ'§ éuD Ñ„Çl6.5Mbps 300Mbps§EWMAŽ{ I••ÝlW = 20 O\ W = 500§ W = 500žEWMA¬¢¦KPDR]žeü &E" 0 0.2 0.4 0.6 0.8 1 -1 -0.5 0 0.5 1 CDF Error DSWA EWMA (a) 100 200 300 400 0 10 20 30 40 50 W 0.5 0.6 0.7 0.8 0.9 1 0 10 20 30 40 50 β 0 20 40 60 80 100 0 10 20 30 40 50 PDR(%) Time(s) accurate measured (b) ê [Ü £Ä802.11n äó´Ÿþ©Û
  26. µ0 3‚ï 5Uµ ÿÁŽ{µ óéþµ Jj 1 µ0 802.11n IO9A^

    802.11n #Eâ ¯K9ƒ'óŠ 2 3‚ï ÿÁ•{ PDR-RSSï „Ç· Ž{ 3 5Uµ ÿÁŽ{µ óéþµ ê [Ü £Ä802.11n äó´Ÿþ©Û
  27. µ0 3‚ï 5Uµ ÿÁŽ{µ óéþµ óéþJ, 0 50 100 150

    0 20 40 60 80 100 Throughput(Mbps) Time(s) {5%,32%} {0%,9%} GradedR Minstrel (a) 1x3 0 50 100 150 200 250 0 20 40 60 80 100 Throughput(Mbps) Time(s) {8%,34%} {0%,8%} GradedR Minstrel (b) 2x3 0 50 100 150 200 250 300 0 20 40 60 80 100 Throughput(Mbps) Time(s) {0%,5%} {9%,42%} GradedR Minstrel (c) 3x3 0 50 100 150 -80 -70 -60 -50 -40 -30 -20 Throughput(Mbps) Ave. RSS(dBm) Minstrel-EWMA Minstrel-DSWA GradedR (d) 1x3 0 50 100 150 200 250 -80 -70 -60 -50 -40 -30 -20 Throughput(Mbps) Ave. RSS(dBm) Minstrel-EWMA Minstrel-DSWA GradedR (e) 2x3 0 50 100 150 200 250 300 -80 -70 -60 -50 -40 -30 -20 Throughput(Mbps) Ave. RSS(dBm) Minstrel-EWMA Minstrel-DSWA GradedR (f) 3x3 ê [Ü £Ä802.11n äó´Ÿþ©Û
  28. µ0 3‚ï 5Uµ ÿÁŽ{µ óéþµ óéþJ, •I© ÿÁµDSWA Ôn µRSS/SNR/SINR/CSI

    ó´ µDѤõÇ(PDR) 3‚¢ÿ .µGradedM Ôn µMIMO§HT20/HT40 ó´ µLGI/SGI þ ] © µGradedR APsµ& \!ªÌ+n STAsµ„Ç››!´dÀJ Database PDR-RSS Model PDR RSS HT-GI-MCS Index Model Application Measure GradedM GradedR DSWA HT-GI-MCS Channel Access Power Control Routing Rate Adaption TX RX Update PHY/MAC Settings 1 ©ÛHT/GI/MCSˆgéUþžÑ K•§•xÑØÓ ˜ ü U ÑeóéþA5¶ 2 (ÜXÚéUцóéþ n܇ ¦§ OUþk ªÌ© ½„ Ç· Ž{" ê [Ü £Ä802.11n äó´Ÿþ©Û