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Nsl seminar(2)


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My presentation in NSL Seminar. The paper is not mine, you could download in IEEE website

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Nsl seminar(2)

  1. 1. Wireless Embedded & Networking System LaboratoryLow-overhead Uplink SchedulingThrough Load Prediction forWiMAX real-time servicesW. Nie, H. Wang, N. Xiong2IET Commun., 2011, Vol. 5, Iss. 8, pp. 1060–1067 Thomhert Suprapto Siadari Dept. IT Convergence Kumoh National Institute of Technology February 3rd., 2012
  2. 2.  Introduction Problems & Solutions WiMAX Sample Frame WiMAX Service Classes Low-overhead Scheduling Simulation Results Conclusion & Future WorksDOC ID
  3. 3.  IEEE802.16 WiMAX 300 trials worldwide Connection oriented PHY & MAC Layer Suffers problem of huge MAC overhead No scheduling Algorithm standardDOC ID
  4. 4. Problems:1. Large overhead uplink scheduling2. Real-time services3. Scheduling algorithmSolutions/ Contributions:1. Low-overhead uplink scheduling2. Load predictionDOC ID
  5. 5.  PMP (BS to MSs) Transmission: Downlink & Uplink TDDDOC ID
  6. 6. WiMAX service classes: Unsolicited Grant Service (UGS)  fixed-size data packets Real-time polling service (rtPS)  generate variable-size data packets periodically Non-real-time polling service (nrtPS)  bandwidth not on the basis of fixed packet size Best Effort (BE)  efficient service (web surfing)DOC ID
  7. 7. - Earlier Deadline First (EDF) scheduling- Adaptive Bandwidth SchedulingDOC ID
  8. 8. - Information Module- Scheduling Database Module- Service Assignment Modulef : frame size (ms), uplink and downlink subframe contains;di : the maximum delay of connection i (ms);qi(t) : the queue length of connection i at time t(bit);si [t, t + f ]: the number of bits required to be transmitted for connection i in the time interval [t, t + f ];ai[t, t + f ]: the number of bits arriving for connection i in the time interval [t, t + f ];Ndi[t, t + f ]: the number of bits waiting in the queue for connection i, which will expire in the time interval [t, t + f ].DOC ID
  9. 9. - Selects SSs based on delay requirement- Suitable for real-time services- Deadline to each packet- Allocate bandwidth to SS based on earliest deadlineInformation Module Firstly  delay requirement rtPS connection input information module: Output: Secondly  expiration timeDOC ID
  10. 10. Scheduling Database Module  serves as a database of information for allconnectionsService Assignment Module- Determine uplink subframe allocation in terms of the number of bits per SSDOC ID
  11. 11. Specific implementation steps:Check BWrtps & Bufferi_deadline (bandwidth required by the deadline frame in cureenttimeIfGuarantee the bandwidth of deadline packetsAllocate more bandwidth to active SSIfThe bandwidth requirement will be scheduled:DOC ID
  12. 12. C: the uplink channel capacity; F: set of all SSs belonging to the rtPS class; Bi: bandwidth allocated to connection i; Dequeue i: remove packet P from the queue of connection i; amount(P,): retrieve the packets P from the connection i. Convert the packets to number of symbols according to the signal-to-interference noise ratio [SINR(ji)] of connection i. CreateIE(amount(P, ji)): create an IE for connection i with amount(P, ji) number of symbols. Then, IE is added to the UL-MAP message. Drop(rtPS): drop packets from the queues for all connections.DOC ID
  13. 13. - Modeling the Arrival ProcessPDF:CDF of inter-arrival time:- Estimation of Time: predict the response time when BS allocates the bandwidth to SS - Tr = Reuest time - Ti = Bandwidth response timeDOC ID
  14. 14. Adaptive time slots calculating:To calculate expected bandwidth:To calculate required time slotsGiven buffer  calculate required time slotSi(0,1)  smooth parameter  give ratio of the actual allocation bandwidth to previous predictions and requirementsIf ε > 1  calculated bandwidth is closer to predicted bandwidthIf ε < 1  calculated bandwidth is closer to requested bandwidthSo, use ω = 0.05 to adjust Si.DOC ID
  15. 15. DOC ID
  16. 16. - Better performance than WFQ & WRR- Sharply reduce MAP & MAC SDUs subheader overhead- Improves system throughputDOC ID
  17. 17. - Problem yg ada itu apa?- Solusi dan kontribusi yang ditwarkan apa?- Metodenya? LOH: EDF & Adaptive sched schem?- EDF utk apa sebenarmya? Ad a 3 module disini? Information module? Sched database module? Service assignment module? Specific implementation steps?- Adaptive sched scheme: modeling Arrival process? estimation time? Adaptive time slots calculating?  apa tujuannya semua ini?- Simulasi  frame ultilisation, average throughput, average queuing delay, packet loss?  kenapa dalam real-time communication harus pake ini? Alasannya?- Dia pake perbandingan WFQ dan WRR? kenapa? Dan hasilnya lebih baik? Kenapa? Ada apa dengann WFQ dan WRR?- Dia kan pake load prediction? Kalo WFQ dan WRR pake load prediction juga gimana?DOC ID