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VoIP over Wireless VoIP over Wireless LANs LANs Sangho Shin Sangho Shin
| Date post: | 03-Jan-2016 |
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VoIP over Wireless VoIP over Wireless LANsLANs
Sangho ShinSangho Shin
OutlineOutline
Why VoIP ?
Why 802.11 ?
My research
Applicability
Why VoIP?Why VoIP?
Personalized ServiceLocation-based ServiceEmergency Service
IP
Voice Service
Why 802.11?Why 802.11?
► Unlicensed channelsUnlicensed channels► Easy to installEasy to install► High speedHigh speed► Widely deployedWidely deployed
VoIP over 802.11 WLANsVoIP over 802.11 WLANs
PBX
InternetInternet
WIFI
AP (Access Point)
My ResearchMy Research
Quality of ServiceQuality of Service for VoIP in 802.11 WLANsfor VoIP in 802.11 WLANs
VoIP (SIP) Client in PDAVoIP (SIP) Client in PDA
SIP = Session Initiation Protocol (RFC 3261)
SIP
VoIP Client in PDAVoIP Client in PDASHARP ZaurusPrototype
ARM chip + Linux
VoIP Client in PDAVoIP Client in PDAFinal product
HandoffHandoff
Handoff Time500 ms ~ 1 s
4 ms ~ 100 ms
Selective Scanning& Caching
Layer 2 (MAC layer) Handoff
ACM MobiWac’04
Selective Scanning & Caching
US PatentApplication No. 60/549,782
2004 Product of the Year Award INTERNET TELEPHONY ® magazine
(www.itmag.com)
1 2 3 4 5 6 7 8 9 10 11
2.402 GHz 2.468 GHz22 MHz
► Selective ScanningSelective Scanning
► CachingCaching LocalityLocality Store the scanned AP information to a cacheStore the scanned AP information to a cache
Layer 2 HandoffLayer 2 Handoff
802.11b channels
HandoffHandoff
Handoff Time 1 min
20 ms ~ 300 ms
Fast L3 Handoff
Passive DAD
Layer 3 (IP layer) Handoff
ACM WICON’06
IEEE Globcom’06
Layer 3 HandoffLayer 3 Handoff
► Fast L3 Handoff (Client side)Fast L3 Handoff (Client side) Fast subnet change detectionFast subnet change detection Scan unused IPs in a new subnetScan unused IPs in a new subnet
► Passive DAD (Server side)Passive DAD (Server side)
160.123.234.31160.123.231.32160.123.235.35160.123.232.36160.123.238.38
160.123.234.32 160.123.234.32 160.123.234.35 160.123.234.36 160.123.234.31 160.123.234.38
VVVV
Request
Response
Monitor Collect IPs Update IP list Fast Response
CapacityCapacity
Theater Stadium
More simultaneous calls
Low VoIP capacity in WLANs
Low bandwidth
Low utilization of VoIP traffic
CapacityCapacity
802.11 MAC
PCF DCF
DPCF
APC
VoIP Capacity 25%~30%
Reduce polling overhead
Fair resource distribution
IEEE WCNC’05 ACM Qshine’06
Call Admission Control (CAC)Call Admission Control (CAC)
WIFI
WIFI
WIFI WIFI
WIFI
WIFI
QoS
Call Admission Control (CAC)Call Admission Control (CAC)
WIFI
WIFI
WIFI WIFI
WIFI
WIFI
QoS
CAC
Call Admission Control (CAC)Call Admission Control (CAC)
CAC
QoS Utilization
90% 80%
CAC with QP-CAT
QoS Utilization
Call Admission Control (CAC)Call Admission Control (CAC)
CAC
QoS Utilization
90% 80%
100% 98%
QP-CAT ?QP-CAT ?
QoS
Delay
Predicted delay with QP-CAT
Capacity for VoIP traffic in 802.11 Capacity for VoIP traffic in 802.11 WLANsWLANs
ExperimentsExperiments
IEEE Infocom‘07
DPCF
APCQP-CAT
ApplicabilityApplicability
ApplicabilityApplicability
802.11 WLAN
Thank you !
ApplicabilityApplicability
802.11
ApplicabilityApplicability
►Voice + Audio + VideoVoice + Audio + Video
IEEE 802.11
Why 802.11?Why 802.11?
IEEE 802.11Standards
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g
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mn p r
sT
u
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wy
Why Voice over IP ?Why Voice over IP ?
►Personalized servicePersonalized service Location based serviceLocation based service
►Ring sound is turned off Automatically in a Ring sound is turned off Automatically in a theatertheater
►When you arrive at home, all calls to you are When you arrive at home, all calls to you are forwarded to home.forwarded to home.
Why 802.11Why 802.11
►802.11 802.11 CSMA/CDCSMA/CD Unlicensed channelUnlicensed channel Shared by many usersShared by many users High SpeedHigh Speed
►802.11a/g : 54 Mb/s802.11a/g : 54 Mb/s►802.11n (MIMO) : 100Mb/s ~ 500Mb/s802.11n (MIMO) : 100Mb/s ~ 500Mb/s
Easy installationEasy installation CheapCheap
BOSS
