1 / 45

Performance Analysis of Scheduling Algorithms for VoIP Services in IEEE 802.16e Systems

Performance Analysis of Scheduling Algorithms for VoIP Services in IEEE 802.16e Systems. Advisor: Dr. Kai-Wei Ke Speaker: Jaw-Woei Ma Date:11/28/2006. Outline. Introduce Scheduling algorithms Analysis of Resource Utilization Efficiency Analysis of VoIP capacity Conclusions References.

dchester
Télécharger la présentation

Performance Analysis of Scheduling Algorithms for VoIP Services in IEEE 802.16e Systems

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Performance Analysis of Scheduling Algorithms for VoIP Services in IEEE 802.16e Systems Advisor: Dr. Kai-Wei Ke Speaker: Jaw-Woei Ma Date:11/28/2006

  2. Outline • Introduce • Scheduling algorithms • Analysis of Resource Utilization Efficiency • Analysis of VoIP capacity • Conclusions • References

  3. Outline • Introduce • Scheduling algorithms • Analysis of Resource Utilization Efficiency • Analysis of VoIP capacity • Conclusions • References

  4. WiMAX • Worldwide Interoperability for Microwave Access(全球微波存取互通性) • A wireless broadband network connection technique. • the last mile. • Cost saving. • Easy to employ

  5. WiMAX

  6. WiMAX • Bandwidth:134Mbps, 300kbps~2Mbps (末端用戶) • Range:48km • Fixed : IEEE 802.16-2004 • Mobile : IEEE 802.16e

  7. Outline • Introduce • Scheduling algorithms • Analysis of Resource Utilization Efficiency • Analysis of VoIP capacity • Conclusions • References

  8. Service class • UGS (Unsolicited Grant Service) : VoIP • rtPS (real-time Polling Service) : MPEG • nrtPS (non-realtime Polling Service) : FTP • BE (Best Effort) : HTTP • ertPS (extended real-time Polling Service) : VoIP (IEEE 802.16e)

  9. Service class • Non-real time Service : nrtPS BE • Real time Service : UGS rtPS ertPS nrtPS and BE are not suitable for VoIP service in IEEE 802.16e systems

  10. Voice Traffic • Markov source model • Enhanced Variable Rate Codec (EVRC) frame duration (Tvc) = 20ms • Voice activity factor = 0.403 • Talk-spurt duration ( 29% Rate 1,4% Rate ½ ,7% Rate ¼ ) • Silence duration ( 60% Rate 1/8 )

  11. Voice Traffic

  12. UGS Algorithm • Generate fixed-size data packets periodically • BS periodically assigns Fixed-size grants to the voice users • The grants size and grants period are negotiated in the initialization process of the voice session

  13. UGS Algorithm

  14. UGS Algorithm • Minimize MAC overhead and uplink access delay • The waste of uplink resources

  15. rtPS Algorithm • Generate variable-size data packets periodically • BS assigns uplink resources that are sufficient for unicast bandwidth request • The grants period are negotiated in the initialization process of the voice session ( bandwidth request process or polling process)

  16. rtPS Algorithm

  17. rtPS Algorithm • More efficiently than UGS • Lager MAC overhead and access delay than UGS and ertPS

  18. ertPS Algorithm • Generate variable-size data packets on a periodically basis • The size of a voice data packet is decreased : Grant Management subheader increased : Bandwidth request header

  19. ertPS Algorithm • The size of data is decreased : using extended PBR (PiggyBack Request) bits of Grant Management subheader • BS assigns uplink resources according to the requested size periodically, until user requests another size of the bandwidth

  20. ertPS Algorithm • The size of data is increased : using BR (Bandwidth Request) bits of Bandwidth request header • BS assigns uplink resources according to the requested size periodically, until user requests another size of the bandwidth

  21. ertPS Algorithm • First bandwidth Allocation the next MAC frame after this bandwidth request process • Second bandwidth Allocation after the bandwidth allocation interval of service flow based on time

  22. ertPS Algorithm

  23. ertPS Algorithm • Reduce MAC overhead and acess delay of the rtPS • Prevent the waste of uplink resources of the UGS

  24. Outline • Introduce • Scheduling algorithms • Analysis of Resource Utilization Efficiency • Analysis of VoIP capacity • Conclusions • References

  25. Resource Utilization Efficiency • UGS algorithm : MAC header ( L h , 6 bytes)

  26. Resource Utilization Efficiency • rtPS algorithm :assume a min polling size ( L1/8 + Lbh ) Lbh : request header : 6 bytes

  27. Resource Utilization Efficiency • ertPS algorithm :

  28. Resource Utilization Efficiency

  29. Resource Utilization Efficiency • Frame Structure

  30. Preamble Broadcast Control DIUC = 0 TDM DIUC a TDM DIUC a TDM DIUC a Preamble DL_MAP UL_MAP Transition Gap Resource Utilization Efficiency • Downlink Subframe

  31. Resource Utilization Efficiency • Size of UL-MAP message is 36 bits ( 4.5bytes ) • UL-MAP message use very robust burst profile (QPSK modulation and 1/12 coding) • When M users use only VoIP Services in one MAC frame, the UGS and ertPS can save (36＊M) bits of downlink resources compared with the rtPS

  32. Resource Utilization Efficiency

  33. Resource Utilization Efficiency • OFDMA Systems • One basic resource unit consists of 48 subcarriers • Voices packet are transmitted by QPSK ½ • UL-MAP are transmitted by QPSK 1/12

  34. Resource Utilization Efficiency

  35. Resource Utilization Efficiency • The total number of wasted resources in the rtPS is larger than that of the UGS • ertPS can save a lot of uplink and downlink resources

  36. Outline • Introduce • Scheduling algorithms • Analysis of Resource Utilization Efficiency • Analysis of VoIP capacity • Conclusions • References

  37. Analysis of VoIP capacity • VoIP capacity is restricted by packet transmission delay bound and radio resource saturation • Analyze packet transmission delay of MAC SDUs (Service Data Units) for the UGS, rtPS and ertPS

  38. Analysis of VoIP capacity • Using OPNET simulator • OFDMA Systems 36 Symbols (Time Domain) 1024 subcarriers (Frequency Domain) downlink : uplink = 2 : 1

  39. Analysis of VoIP capacity • Total number of downlink and uplink resources are 384 and 140 one resource unit consists of 48 subcarries downlink / uplink resources are scheduled by RR ( round-robin )

  40. Analysis of VoIP capacity

  41. Analysis of VoIP capacity • Delay bound is 60 ms, the max supportable number: UGS : 68 / rtPS : 76 / ertPS : 92 • ertPS can support more 21% : UGS / 35% : rtPS

  42. Outline • Introduce • Scheduling algorithms • Analysis of Resource Utilization Efficiency • Analysis of VoIP capacity • Conclusions • References

  43. Conclusions • ertPS can solve these problems of the UGS and rtPS UGS : waste of uplink resources rtPS : MAC overhead and access delay • VoIP capacity : ertPS > UGS > rtPS

  44. Conclusions • ertPS could be used efficiently in any wireless communication systems that support VoIP services with variable data rates and slience suppression

  45. References [1] Howon Lee, Taesoo Kwon, Dong-Ho Cho, Geunhwi Lim and Yong Chang“Performance Analysis of Scheduling Algorithms for VoIP Services in IEEE 802.16e Systems” Vehicular Technology Conference, 2006. VTC 2006-Spring. IEEE 63rd [2] IEEE 802.16 standard [3] IEEE 802.16e

More Related