WiMax Review Problem Statement Traffic Model Scheduling Protocol Overhead Conclusion and Future WorkWiMax SchedulingJingyi Shaoshao14@eecsEE228a, UC BerkeleyMay 2, 2006WiMax Review Problem Statement Traffic Model Scheduling Protocol Overhead Conclusion and Future WorkOutline1WiMax Review2Problem Statement3Traffic Model4Scheduling Protocol5Overhead6Conclusion and Future WorkWiMax Review Problem Statement Traffic Model Scheduling Protocol Overhead Conclusion and Future WorkOverviewIEEE Standard 802.16, PHY layer and MAC layer .Wireless MAN, cellular infrastructure.Support LOS in 10-66 GHz and non-LOS in 2-11 GHz.Flexible bandwidth allocation.Better QoS support, 4 scheduling classes.Optional advanced AAS (MIMO), HARQ, and Mesh support.Security features.Mobility support.WiMax Review Problem Statement Traffic Model Scheduling Protocol Overhead Conclusion and Future WorkPHY Layer OverviewWirelessMAN SC (Single Carrier 10-66 GHz).WirelessMAN SCa (Single Carrier 2-11 GHz).WirelessMAN OFDM (2-11 GHz).WirelessMAN OFDMA (2-11 GHz).WirelessHUMAN (Wireless High-speed Unlicensed MAN).TDD and FDD.BPSK, QPSK, 16-QAM, and 64-QAM.FEC.WiMax Review Problem Statement Traffic Model Scheduling Protocol Overhead Conclusion and Future WorkMAC Layer OverviewPMP (Point to Multi-Point).Adaptive DL-subframe and UL-subframe.Contention-free.UGS, rtPS, nrtPS, (ertPS), BE.WiMax Review Problem Statement Traffic Model Scheduling Protocol Overhead Conclusion and Future WorkOFDMA Frame StructureWiMax Review Problem Statement Traffic Model Scheduling Protocol Overhead Conclusion and Future WorkProblem StatementAssumptions:One cell.Channel conditions for all SS are similar so that all SS use thesame modulation scheme and coding rate.Fixed sub-frame division.All connections are MPEG type of video traffic.Ignore overheads from higher layers.Ignore pilot and null OFDM sub-carriers.Problem: model and simulate the network traffic using rtPSscheduling.WiMax Review Problem Statement Traffic Model Scheduling Protocol Overhead Conclusion and Future WorkOFDMA and MAC ParametersFFT size: 1024.OFDM symbol time: 100 µs.Data burst modulation: 16-QAM.Data burst FEC rate:12.Map overhead modulation: QPSK.Map overhead FEC rate:112.MAC frame duration: 5 ms. (50 OFDM symbols)Ratio of DL-subframe to UL-subframe is 2:1. (DL maxcapacity 27 Mbps.)WiMax Review Problem Statement Traffic Model Scheduling Protocol Overhead Conclusion and Future WorkrtPS ParametersMinimum reserved traffic rate (bits/second).Maximum sustained traffic rate (bits/second).Maximum latency (ms).Request/Transmission policy.WiMax Review Problem Statement Traffic Model Scheduling Protocol Overhead Conclusion and Future WorkVBR Video Traffic ModelFirst order AR model [Maglaris, et al. 88].x(n + 1) = ax (n) + bw (n)where a and b are constant parameters, and w (n) is a whiteGaussian process with mean µ and variance 1. x (n) is the numberof bits per pixel of the nth video frame.Other models [Heyman, et al 92, 94; Dawood, et al. 99].WiMax Review Problem Statement Traffic Model Scheduling Protocol Overhead Conclusion and Future WorkVideo Model ParametersVideo rate: 25 frame/second.Video frame dimension: 40000 pixels.a = 0.8781b = 0.1108µ = 0.572Truncate each video frame if out of range.0 100 200 300 400 500 600024681012x 105Time (second)Video Data Rate (bits/second)Sample Video StreamWiMax Review Problem Statement Traffic Model Scheduling Protocol Overhead Conclusion and Future WorkScheduling ProtocolsAssuming total n connections (in either DL or UL). Label theconnections 1 to n.1Schedule the first K connections such thatPKi =1xi≤ C butPK +1i =1xi> C .2Schedule the first K connections. And then search throughthe rest of the connections in order to schedule additional K0connections that would fit in the bandwidth.3Re-order the connections in increasing order, and thenschedule the first K . i.e. Schedule the smallest K connections.4Randomly re-order the connections, and then schedule thefirst K .WiMax Review Problem Statement Traffic Model Scheduling Protocol Overhead Conclusion and Future WorkScheduling 1 and 2, 50 connections, DL0 5 10 15 20 25 30 35 40 45 500100200300400500600ConnectionDelay (second)Connection vs. Delayscheduling1scheduling2WiMax Review Problem Statement Traffic Model Scheduling Protocol Overhead Conclusion and Future WorkScheduling 3 and 4, 50 connections, DL0 5 10 15 20 25 30 35 40 45 50360365370375380385390395400405ConnectionDelay (second)Connection vs. Delayscheduling3scheduling4WiMax Review Problem Statement Traffic Model Scheduling Protocol Overhead Conclusion and Future WorkScheduling 3 and 4, 15 connections, DL0 5 10 1500.020.040.060.080.10.120.140.160.180.2ConnectionDelay (second)Connection vs. Delayscheduling3scheduling4WiMax Review Problem Statement Traffic Model Scheduling Protocol Overhead Conclusion and Future WorkScheduling 3 and 4, 20 connections, DL0 2 4 6 8 10 12 14 16 18 2052545658606264666870ConnectionDelay (second)Connection vs. Delayscheduling3scheduling4WiMax Review Problem Statement Traffic Model Scheduling Protocol Overhead Conclusion and Future WorkNon-Allocated Resource (bits/second), DL0 100 200 300 400 500 60000.511.522.53x 106Time (second)Resource left (bits/second)Scheduling 10 100 200 300 400 500 60000.511.522.53x 106Scheduling 3Time (second)Resource left (bits/second)0 100 200 300 400 500 60000.511.522.53x 106Time (second)Resource left (bits/second)Scheduling 20 100 200 300 400 500 60000.511.522.53x 106Scheduling 4Time (second)Resource left (bits/second)WiMax Review Problem Statement Traffic Model Scheduling Protocol Overhead Conclusion and Future WorkImprovements On Delay, Scheduling 3 and 4, 20Connections0 2 4 6 8 10 12 14 16 18 2040424446485052545658ConnectionDelay (second)Connection vs. Delayscheduling3scheduling40 2 4 6 8 10 12 14 16 18 20354045505560ConnectionDelay (second)Connection vs. Delayscheduling3scheduling4WiMax Review Problem Statement Traffic Model Scheduling Protocol Overhead Conclusion and Future WorkConnection Jitter0 100 200 300 400 500 600 7000102030405060Connection JitterTime (second)Delay (second)Scheduling3Scheduling40 100 200 300 400 500 600 7000102030405060Time (second)Delay (second)Connection JitterScheduling3Scheduling4WiMax Review Problem Statement Traffic Model Scheduling Protocol Overhead Conclusion and Future WorkDL-MAP Overhead96 + 36K bits where K is the number of connections allocated.WiMax Review Problem Statement Traffic Model Scheduling Protocol Overhead Conclusion and Future
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