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1 The Design of the Power Saving Mechanisms in IEEE 802.16e Networks (Defense) Student: Lei Yan ( ) Advisor: Dr. Ho-Ting Wu ( ) Date: 2009/07/23 Institute of Computer Science and Information Engineering, National Taipei University of Technology Slide 2 2 Outlines Backgrounds and motivation Spec-defined power saving mechanism Proposed power saving mechanism Performance evaluation Conclusion and future works Slide 3 3 Brief of IEEE 802.16 Also called WiMAX (Worldwide Interoperability for Microwave Access) The wireless last mile technology Low cost and free to geographical limits Includes PHY/MAC solutions Higher transmission rate than 3.5G Ideal transmission rate and coverage: 75 Mbps and 50 km Now been merchandised in Taiwan Slide 4 4 Layering related to connections Convergence sublayer Classification Common Part sublayer Establishment Change Deletion Call admission control (CAC) Bandwidth allocation (BWA) Packet scheduling Security sublayer Encryption/Decryption for data MAC Common Part Sublayer (CPS) Slide 5 5 Frame structure of WiMAX Slide 6 6 Outlines Backgrounds and motivation Spec-defined power saving mechanism Proposed power saving mechanism Performance evaluation Conclusion and future works Slide 7 7 Renaming for QoS metrics: Power saving class (PSC) HTTP BE FTP NRTVR nrtPS MPEG RTVR rtPS VoIP (silence suppressi on) ERTVR ertPS VoIP UGS Usage Service type for power saving Service type PSCReal-time Non-Real time PSC I NRTVR (nrtPS) BE PSC II UGS RTVR (rtPS) PSC III ERTVR (ertPS) Slide 8 8 States of a MS with power saving function Slide 9 9 Outlines Backgrounds and motivation Spec-defined power saving mechanism Proposed power saving mechanism Performance evaluation Conclusion and future works Slide 10 10 What our research work has done? Includes UGS/ertPS, rtPS, nrtPS, and BE for both UL/DL traffics Integrated consideration to CENTRALLY arrange calls to prolong sleep durations Complete solution (CAC + BWA + packet scheduling) Reduction of ON-OFF alternations in MS Q: Why packet scheduling for power saving? A: Since BS can control all states for MS PRECISELY with time Slide 11 11 Structure of our research work Slide 12 12 Assumptions for our research work Frame overflow is allowed (to schedule across the bound between frames) Merge the listening duration into ON- state duration Slide 13 13 BWA and scheduling Slide 14 14 Judgment in the proposed BWA algorithm (5) determines the credit. (6) is the stabilized version of (7) Slide 15 15 Deployed packet scheduling algorithm Round-Robin fashion for the scheduling Pros: In the algorithm itself, all MSs have intact sleep duration (intuitive design) Cons: No guarantee for UGS/ertPS delay Special assumption: all delay bounds are set and equal to DUGS (100 ms) Slide 16 16 Outlines Backgrounds and motivation Spec-defined power saving mechanism Proposed power saving mechanism Performance evaluation Conclusion and future works Slide 17 17 System structure of our research work Slide 18 18 Parameters for simulation Number of BS1 Number of MS20~200 System capacity (Mbps)50 Frame duration (ms)5 Capacity per frame (byte)31250 Amplification ratio5, 10, 15, and 20 Simulation duration (sec)500 Call duration (sec)Uniform(60,200) Slide 19 19 Parameters for simulation (cont.) Service type UGSertPSrtPSnrtPSBE Delay bound (ms) 100 200300400 Transmission rate required in call request (kbps) 64 Uniform(48, 60) Bandwidth request size per frame (byte) 40 Uniform(30, 50) Arrival rate 0.44 0.030.020.20 ON/OFF ratio for ertPS 0.4/0.6 Slide 20 20 The traditional WiMAX scheme we compare to No BWA and scheduling (no packet dropping rate/delay) We amplified the negative credit to reduce packet dropping/delay ItemsProposedTraditional CAC algorithm in use Traditional Aggregation for grant size YESNO Adaptively adjust the grant size YESNO Frame overflowAllowedNot allowed RF device is allowed to be turned off YESNO Slide 21 21 Three scenarios for our comparison Slide 22 22 Flow chart of the program Slide 23 23 Increase of sleeping ratio Heavier loading causes longer C but reduce number of cycle (number of granting for MSs) => avg. proportion in ON-state is decreased Slide 24 24 Scenario 1: AMP=15 Slide 25 25 Slide 26 26 Scenario 2: AMP=20 Slide 27 27 Slide 28 28 Slide 29 29 Slide 30 30 Scenario 3: MS=120 Slide 31 31 Slide 32 32 Scenario 4: MS=200 Slide 33 33 Slide 34 34 Slide 35 35 Slide 36 36 Outlines Backgrounds and motivation Spec-defined power saving mechanism Proposed power saving mechanism Performance evaluation Conclusion and future works Slide 37 37 Conclusion Although the power saving based WiMAX scheme introduces packet dropping and delay than the traditional one, the power consumption is decreased Our proposed WiMAX scheme prolongs sleep duration and decreases ON-OFF alternation for MSs Proposed BWA + scheduling is better than NO BWA + scheduling in both packet dropping rate and delay The current judgment for parameters can make MSs sleep at most 15 frames with tolerable packet dropping rate Slide 38 38 Future works Further judgment for parameters to make the packet dropping rate tolerable when AMP=20 Use the LMS algorithm as substitute for BWA Implement the other two packet scheduling algorithm for alternative Slide 39 39 Thank you!! 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