2007 IEEE 802.11e LAN VoIP 2008 2 4 3606U075-2
1 5 1.1...................................... 5 1.2...................................... 5 1.3..................................... 6 2 IEEE 802.11e LAN 7 2.1 LAN.................................. 7 2.1.1 IEEE802.11................................. 7 2.1.2 ISM................................. 7 2.1.3 CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance). 8 2.1.4 Dynamic TDMA (Time Division Multiple Access)............ 9 2.2 IEEE 802.11e.................................... 9 2.2.1 IEEE 802.11e................................ 9 2.2.2 QoS (Quality of Service).......................... 9 2.2.3 EDCA (Enhanced Distributed Channel Access)............. 10 2.2.4 HCCA (Hybrid Coordination Function Controlled Channel Access).. 11 2.2.5 WMM (Wi-Fi Multimedia)......................... 11 2.2.6 TOS Type Of Service................... 11 3 VoIP 12 3.1...................................... 12 3.2 VoIP................................ 12 3.3..................................... 12 3.4 CODEC....................................... 13 3.5............................. 14 3.5.1.................................... 14 3.5.2................................ 15 1
3.6 VoIP........................... 15 3.6.1 MOS..................................... 15 3.6.2 PSQM.................................... 16 3.6.3 PESQ.................................... 16 3.6.4 R..................................... 17 4 VoIP 19 4.1......................................... 19 4.2...................................... 19 4.2.1............................. 19 4.2.2........................ 21 4.3 1:................ 21 4.3.1.................................. 21 4.3.2.................................. 21 4.3.3.................................. 22 4.4 2: Best Effort............. 22 4.4.1.............................. 22 4.4.2.................................. 23 4.5 3: 3........... 23 4.5.1.............................. 23 4.5.2.................................. 24 4.6 1 3........................... 24 4.6.1..................................... 24 4.6.2..................................... 24 4.7 4: Best Effort.. 25 4.7.1.................................. 25 4.7.2.................................. 26 5 29 5.1........................................ 29 5.2...................................... 29 2
2.1 CSMA/CA..................................... 8 4.1....................................... 20 4.2 3.................................... 24 4.3 CW......................................... 26 4.4 AIFS......................................... 26 4.5 TXOP........................................ 27 4.6 R..................... 27 4.7 R......... 28 3
3.1............................... 14 3.2 ITU-T G.114...................... 14 3.3 MOS................................... 16 3.4 IP................................ 17 4.1................................ 20 4.2 1 Mbps.................. 21 4.3 1 R Mbps...................... 22 4.4 2 Mbps.................. 22 4.5 2 R Mbps...................... 23 4.6 3-1 Mbps................. 23 4.7 3-2 Mbps................. 23 4.8 EDCA.......................... 25 4.9 4 Best Effort......................... 25 4.10 4 R Mbps............... 26 4.11 4................. 27 4
1 1.1 IP (Best Effort) ( ) QoS (Quality of Service) 1.2 QoS IEEE 802.11e LAN QoS VoIP QoS VoIP VoIP QoS 5
1 1.3 1 2 IEEE 802.11e IEEE 802.11e 3 VoIP (Voice over Internet Protocol) VoIP 4 VoIP EDCA IEEE 802.11e VoIP EDCA (QoS) 5 6
2 IEEE 802.11e LAN 2.1 LAN 2.1.1 IEEE802.11 LAN IEEE Institute of Electrical Electronics Engineers 1990 IEEE 802.11 Wireless LAN WG 1997 LAN IEEE 802.11 IEEE 802.11 ISM 3 1Mbps 2Mbps 2 1999 IEEE 802.11b IEEE 802.11b 11Mbps 54Mbps IEEE 802.11b IEEE 802.11g IEEE 802.11b 5GHz IEEE 802.11a 3 IEEE 802.11i QoS IEEE 802.11e IEEE 802.11n 2.1.2 ISM ISM (industrial Scientific Medical) 900MHz (902-928MHz) 2.4GHz (2400-2500MHz) 5.7GHz (5725-5859MHz) 3 7
2 IEEE 802.11E LAN 2.4GHz LAN ISM 2.1.3 CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) CSMA/CD (Carrier Sense Multiple Access with Collision Detection) CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) CSMA/CA IFS = Inter Frame Space ACK ACK CSMA/CD 2.1: CSMA/CA 8
2 IEEE 802.11E LAN 2.1.4 Dynamic TDMA (Time Division Multiple Access) TDMA (Time Division Multiple Access) 1 2 PDC GSM TDMA Dynamic TDMA TDMA 2.2 IEEE 802.11e 2.2.1 IEEE 802.11e 2.1.1 IEEE 802.11e IEEE( ) LAN 802 IEEE 802.11a IEEE 802.11b QoS QoS QoS EDCA CSMA/CA QoS HCCA Dynamic TDMA IEEE 802.11a IEEE 802.11b IEEE 802.11e 2.4GHz 5.2GHz 2 2.2.2 QoS (Quality of Service) QoS ATM ( ) QoS QoS EDCA Enhanced Distributed Channel Access HCCA Hybrid Coordination Function Controlled Channel Access 2 IEEE 802.11e QoS 9
2 IEEE 802.11E LAN 2.2.3 EDCA (Enhanced Distributed Channel Access) EDCA LAN CSMA/CA 2.1.3 CSMA/CA EDCA EDCA 4 AC Access Category 4 AC-BK AC-BE AC-VI AC-VO CSMA/CA 3 AIFS Arbitration IFS CW Contention Window TXOP Transmission Oppotunity AIFS (Arbitration IFS) AIFS AIFS ms CW (Contention Window) CW (Contention Window) 10
2 IEEE 802.11E LAN 0 CW CW CWmin CWmax CWmin CW CWmax CW 2 CWmax TXOP (Transmission Opportunity) TXOP TXOP 0 1 ms 2 AckPolicy Ack ACM Admission Control Mandatory 2.2.4 HCCA (Hybrid Coordination Function Controlled Channel Access) HCCA PCF Point Coordination Function QoS 2.2.5 WMM (Wi-Fi Multimedia) Wi-Fi Alliance EDCA QoS IEEE 802.11e QoS WMM 2.2.6 TOS Type Of Service EDCA TOS TOS 8 6 DSCP Differentiated Services Code Point Diffserv 11
3 VoIP 3.1 VoIP Voice over Internet Protocol IP VoIP IP IP 3.2 VoIP IP QoS (Quality of Service) QoS VoIP 3.3 VoIP (CODEC) IP 12
3 VOIP 3.4 CODEC 3 15 64Kbit/s 1 7Kbit/s 4 30Kbit/s 3.1 13
3 VOIP 3.1: G.711 G.723.1 G.729A 64Kbit/s 5.3/6.3Kbit/s 8Kbit/s 160byte 20/24byte 20byte (IP,UDP,RTP) 40byte 40byte 40byte 20ms 30ms 20ms 80Kbit/s 15.9 16.8Kbit/s 24Kbit/s 3.5 3.5.1 VoIP End-to-End 150ms 400ms ITU-T (International Telecommunication Union Telecommunication sector ) G.114 3.2: ITU-T G.114 (ms) 0 150 150 400 400 CODEC CODEC 14
3 VOIP 1 RTP/UDP/IP IP 1 IP 1 IP 3.5.2 ms 3.6 VoIP 3.6.1 MOS ITU International Telecommunication Union P.800 MOS (Mean Opinion Score) 5 MOS MOS 15
3 VOIP 3.3: MOS 5 (Excellent) 4 (Good) 3 (Fair) 2 (Poor) 1 (Bad) 3.6.2 PSQM ITU-T 1996 PSQM (Perceptual Speech Quality Measure) 0 6.5 MOS PSQM MOS PSQM IP PSQM CODEC IP MOS PSQM IP 3.6.3 PESQ 2001 ITU-T PSQM PESQ (Perceptual Evaluation of Speech Quality) IP PESQ PSQM IP PSQM PSQM PESQ 16
3 VOIP MOS PESQ 0.5 4.5 MOS PSQM PESQ R PESQ IP R PESQ 3.6.4 R ITU-T G.107 G.113 R E-model 20 TTC 17 R 0 100 2002 IP 050 C 3.4: IP R A B C 80 100ms 70 150ms 50 400ms R 2 1. R MOS ITU-T G.107 TTC (The Telecommunication Technology Committee 17
3 VOIP ) JJ-201.01 R MOS R MOS MOS 2. IP ITU-T G.107 R IP ITU-T G.113 R R = R o I s I d I e + A R o I s I d I e A 18
4 VoIP 4.1 4.2 4.2.1 4.1 4.1 W Z F A E IEEE 802.11b EDCA QoS IEEE 802.11e iperf UDP TOS IP Tables 19
4 VOIP 4.1: 4.1: A B C CPU Core 2 Duo U7500 Core 2 Duo T7250 Pentium M 2.0GHz 2.0GB 2.0GB 1.0GB OS Windows XP Professional Windows XP Professional Windows XP Professional D E F CPU Core 2 Duo T7250 Pentium M 1.8GHz 2.0GB 512MB OS Windows XP Professional Windows XP Professional W X Y Z CPU Core 2 Duo U7500 Core 2 Duo T7250 Pentium 3 800MHz 2.0GB 2.0GB 384MB OS Windows XP Professional Windows XP Professional Windows XP Professional 20
4 VOIP 4.2.2 Astec Eyes for VoIP Version 4.200 CODEC VoIP G.723.1 R R CIAJ Communications and Information network Association of Japan IP (CES-Q003-1) 5 R 5 4.3 1: 4.3.1 IEEE802.11e EDCA VoIP 4.3.2 4.2 4 Voice R 60Kbps F E Voice W A X B Back Ground Y C Best Effort G D Video 4.2: 1 Mbps Video 5 10 Best Effort 10 5 Back Ground 60 50 50 50 60Mbps 21
4 VOIP Back Ground 4.3.3 4.3 4.3: 1 R Mbps Video 5 10 Best Effort 10 5 Back Ground 60 50 50 50 R 78.0 32.8 34.3 49.3 4.3 Best Effort 2 Best Effort 4.4 2: Best Effort 4.4.1 4.4 Video 5Mbps Back Ground 55Mbps Best Effort 1 Voice R 60Kbps 4.4: 2 Mbps Video 5 5 5 5 Best Effort 0 1 2 3 Back Ground 55 55 55 55 22
4 VOIP 4.4.2 4.5 4.5: 2 R Mbps Video 5 5 5 5 Best Effort 0 1 2 3 Back Ground 55 55 55 55 R 71.4 49.5 43.7 32.2 Best Effort 4.5 3: 3 4.5.1 2 Best Effort 4 IEEE802.11e 3 3 2 Video Best Effort 1. Voice Video Back Ground 4.6: 3-1 Mbps Video 0 1 2 3 4 5 Back Ground 60 60 60 60 60 60 2. Voice Best Effort Back Ground 4.7: 3-2 Mbps Best Effort 0 1 2 3 4 5 Back Ground 60 60 60 60 60 60 23
4 VOIP R Voice 60Kbps 4.5.2 4.2 4.2: 3 4.2 Video Best Effort R 3 Best Effort 4.6 1 3 4.6.1 1 3 IEEE802.11e EDCA Best Effort 4.6.2 VoIP Best Effort Best Effort Web Best Effort Best Effort Best Effort EDCA EDCA 24
4 VOIP 4.7 4: Best Effort 4.7.1 Best Effort Best Effort 3 EDCA 4.8 4.8: EDCA CWmin CWmax AIFS TXOP Voice 3 7 1 1504 Video 7 15 1 3008 Best Effort 15 63 3 0 Back Ground 15 1023 7 0 Best Effort 2 Video 4 Back Ground 2 4.9 4.9: 4 Best Effort CWmin CWmax AIFS TXOP Best Effort 7 15 15 1023 1 7 0 3008 1 60Mbps R 4.10 R EDCA R 43.5 3.6.4 IP 050 Best Effort R VoIP 25
4 VOIP 4.10: 4 R Mbps Video 2.5 Best Effort 2.5 Back Ground 55 R 43.5 4.7.2 4.3 4.4 4.5 4.3: CW 4.4: AIFS 26
4 VOIP 4.5: TXOP CW CW min = 15 AIFS TXOP R Best Effort R 4.11 4.6 4.11: 4 CWmin CWmax AIFS TXOP Best Effort 15 63 1023 3 7 0 4.6: R R IP C 27
4 VOIP 4.7: R R R IEEE802.11e EDCA 28
5 5.1 IEEE 802.11e VoIP VoIP EDCA Best Effort EDCA IP skype VoIP VoIP IEEE 802.11e QoS QoS VoIP IEEE802.11e EDCA EDCA 5.2 Best Effort 29
5 UDP TCP UDP CODEC G.721.1 CODEC QoS EDCA HCCA 30
NTT 11e TEAM GOTO LOVE 6 31
[1] ITU-T Recommendation G.107, The E-model, a computational model for use in transmission planning, March 2005. [2] ITU-T Recommendation G.113, Transmission impairments due to speech processing, February 2001. [3] ITU-T Recommendation G.114, One-way transmission time, March 2005. [4] ITU-T Recommendation G.723.1, Dual rate speech coder for multimedia communications transmitting at 5.3 and 6.3 kbit/s, February 2002. [5] ITU-T Recommendation P.800, Methods for subjective determination of transmission quality, August 1996. [6] ITU-T Recommendation P.861, Objective quality measurement of telephone-band (300-3400 Hz) speech codecs, February 1998. [7] ITU-T Recommendation P.862, Perceptual evaluation of speech quality (PESQ), an objective method for end-to-end speech quality assessment of narrowband telephone networks and speech codecs, February 2001. [8] W.R. Stevens,,, TCP/IP,, 1997. [9],,, TCP/IP ( ),, 1994. [10], QoS,, 2001. [11], IEEE802.11e VoIP, 2006, 2007. [12], IEEE802.11e VoIP, 2006, 2007. 32
[13], Diffserv, 2003, 2004. [14], DiffServ AF, 2003, 2004. [15], LAN, 2003, 2004. [16], UDP, 2003, 2004. [17], DiffServ VoIP, 2002, 2003. 33