Performance Analysis of VoIP over WiMax

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Performance Analysis of VoIP over WiMax
MTP- II Presentation Project Guide Prof. Huzur
Saran
23rd May, 2007
Presented by Vikram Agrawal
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Agenda

• IEEE 802.16 An attractive alternative
• QoS support in Mac Layer
• Voice over IP
• Performance metrics
• Simulation and Results
• Future work

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IEEE 802.16 An attractive alternative

• Increasing demand for broadband access.
• Serves worlds rural and sub-urban places
• High data rates and connectivity
• NLOS performance and mobility

Support for Voice calls ??
Video on Demand ??
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QoS support in Mac Layer
QoS Functions within BS and SSs Source CELM06
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Issues with VoIP

• Low Efficiency

IP/UDP/RTP header
MAC Header
Payload
Efficiency lt 50
20 Bytes
40 Bytes
10-30 Bytes
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Issues with VoIP
Voice conversation
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Issues with VoIP

• Voice Activity Detector
• 60 of a Voice conversation is silence
• Talk spurts - on state
• Silence Gaps - off state

• Continuous Process (10ms)
• 10 bytes

ON
ACT frame

• Exponential process
• Background Noise
• 2 bytes

OFF
SID frame
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VoIP over WIMAX

• MAC scheduling for VoIP traffic
• UGS or rtPS ?
• Grant interval size
• Voice Traffic model
• Admission Control for new VoIP client
• Resource availability
• QoS policy

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Simulation Done

• Used Wimax module for NS2
• Used tele-traffic theory for network flow
• Inter arrival time and Call holding time is
  exponentially distributed
• To model Spurts and Gaps, exponential
  distribution is used
• Call admission control is based on resource
  availability

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Performance Metrics

• Throughput
• Resource utilization
• Transmission delay
• Latency
• Call dropped
• Call in progress

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UGS vs rtPS
Num of nodes 5 AHT 60 sec AIT 2 sec
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Constant Bit Rate Voice Traffic
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Constant Bit Rate Voice Traffic
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Constant Bit Rate with Spurts and Gaps
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Constant Bit Rate with Spurts and Gaps
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Comparison
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Comparison
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Grant Interval
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Grant Interval
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Varying Grant Interval
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Varying Grant Interval
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Varying Number of Service Station
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Varying Number of Service Station
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Future Work

• Voice Traffic with data traffic
• Using Wimax test bed with quality of voice
  received as a QOS constraint
• Considering voice calls between SSs and not only
  between SS and BS

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References

• C. Cicconetti, C. Eklund, L. Lenzini, and E.
  Mingozzi. Quality of service support in IEEE
  802.16 networks. IEEE Network, 205055, March
  2006.
• C. Cicconetti, C. Eklund, L. Lenzini, and E.
  Mingozzi. Performance evaluation of the IEEE
  802.16 MAC for QoS support. IEEE Trans. Mobile
  Comput., 62638, January 2007.
• Oleg Gusak, Neal Oliver, and Khosrow Sohraby.
  Performance evaluation of the 802.16 medium
  access control layer. In ISCIS, pages 228237,
  2004.
• Draft of WiMax Standard, "IEEE Standard for Local
  and Metropolitan Area Networks - Part 16 Air
  Interface for Fixed Broadband Wireless Access
  Systems", IEEE 802.16 forum.
• Carl Eklund, Roger B. Markas, and Kenneth L.
  Stanwood, "IEEE Standard 802.16 A technical
  overview of the wireless MAN Air Interface for
  Broadband Wireless Access", IEEE Communications
  Magazine, pp 98-107, June 2002.

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References

• Jenhui Chen, Chih-Chieh Wang, Frank Chee-Da Tsai,
  Chiang-Wei Chang,Syao-Syuan Liu, Jhenjhong Guo,
  Wei-Jen Lien, Jui-Hsiang Sum, and Chih-Hsin Hung.
  The design and implementation of wimax module for
  ns-2 simulator.In WNS2 06 Proceeding from the
  2006 workshop on ns-2 the IP network simulator,
  page 5, New York, NY, USA, 2006. ACM Press.
• Jorn Seger. Modelling approach for voip traffic
  aggregations for transferring tele-traffic trunks
  in a qos enabled ip-backbone environment, 2003.
• W. Jiang and H. Schulzrinne. Analysis of on-off
  patterns in voip and their effect on voice
  traffic aggregation, 2000.
• David Tse and Pramod Viswanath. Fundamentals of
  wireless communication. Cambridge University
  Press, New York, NY, USA, 2005.

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• Questions ?
• Suggestions ?

Thank You