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AN ENERGY-EFFICIENT SCHEDULING FOR MULTIPLE MSSS IN IEEE 802.16E BROADBAND WIRELESS. Shih-Chang Huang, Chien Chen, and Rong-Hong Jan, and Cheng-Chung Hsieh IEEE 19 th Personal, Indoor and Mobile Radio Communications, 2008. (PIMRC 2008). Outline. Introduction MWT and feasible slot allocation
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AN ENERGY-EFFICIENT SCHEDULING FOR MULTIPLE MSSS INIEEE 802.16E BROADBAND WIRELESS Shih-Chang Huang, Chien Chen, and Rong-Hong Jan, and Cheng-Chung Hsieh IEEE19th Personal, Indoor and Mobile Radio Communications, 2008. (PIMRC 2008)
Outline • Introduction • MWT and feasible slot allocation • Energy efficiency scheduling for multiple MSSs • Simulation • Conclusion
Introduction • The MSS simply sleeps for a predefined period of time and then returns to normal operation to save power. • We first focus our efforts on finding the minimum wakeup time and arrange for multiple MSSs to achieve maximum bandwidth utilization.
Minimum wakeup time OFDM Frame Delay Constraint of C1 C1 3 4 1 2 5 6 7 8 9 0 Delay Constraint of C2 C2 a b c d e Minimum Delay Constraint
Feasible slot allocation OFDM Frame Delay Constraint of C1 C1 3 4 1 2 5 6 7 8 9 0 Delay Constraint of C2 C2 a b c d e 1 2 3 a 5 6 b 4 7 d 8 c Minimum Delay Constraint Data ready Feasible slots
Ford-Fulkerson Algorithm a /2 0 /2 0 1 S D /1 0 1 1 0 /2 2 1 0 /2 b
Scheduling for multiple MSSs OFDM Frame MSS A A MSS B B Feasible slots MWTblocks OFDM frames 1 A 0/1 0/1 0/1 1/1 1/1 S 1/1 0/1 2 D 0/1 B 1/1 1/1 0/1 0/1 1/1 0/1 3
Scheduling for multiple MSSs MWT Cycle = 8 MWT Cycle = 2 LCM(8,2) = 8
Scheduling for multiple MSSs MWTblocks OFDM frames A1 1 2 A2 3 A3 4 S B1 D 5 B2 6 B3 7 B4 8
Scheduling for multiple MSSs • If MWT blocks is larger than OFDM frames, we know that there are no feasible schedules. • If the feasible slot size is large, it is possible that the blocks of a MSS may lose the order of their generation sequence. However, this problem will not influence the schedule result.
The Time Complexity • The time complexity of the Ford-Fulkerson maximum flow algorithm is known as O(n3) • Nodes in the schedule graph is • Total time complexity is
Simulation • Traffic arrival time: 20ms to 40ms • QoS delay constraint: 200ms to 400ms • Generated packet size: 250 Bytes to 400 Bytes • Maximal data rate that BS offers to all MSSs is 2 Mbps
Conclusion • We propose an energy-efficient traffic scheduling approach for multiple MSSs in 802.16e broadband wireless networks. • We let all MSSs achieve a goal to minimize the wakeup time and apply the Ford-Fulkerson maximum flow algorithm to obtain a feasible schedule.