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An enhanced uplink scheduling scheme for IEEE 802.16 metropolitan area networks. Chia -Yu Yu 1 , Sherali Zeadally 2 , Naveen Chilamkurti 3 , Ce-Kuen Shieh 1
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An enhanced uplink scheduling scheme forIEEE 802.16 metropolitan area networks Chia-Yu Yu1 , Sherali Zeadally2, Naveen Chilamkurti3, Ce-Kuen Shieh1 1Institute of Computer Communication Engineering and Department of Electrical Engineering, National Cheng Kung University, Taiwan 2 Department of Computer Science and Information Technology University of the District of Columbia, Washington 3Dept. of Computer Science and Computer Engineering, La Trobe University, Melbourne, Australia International Conference On Mobile Technology, Applications, And Systems, (ACM Mobility Conference )2008
Outline • Introduction • Background • Related works • Proposed adaptive deficit priority queue (ADPQ) scheme • Simulation • Conclusion
Introduction • IEEE 802.11 (disadvantages) • Low transmission rates • Short transmission distances • IEEE 802.16 (advantages) • High speed access to internet • Broad coverage range • QoS support • Fast deployment and low costs
Introduction • Some papers [4] [5] proposed scheduling schemes to achieve the following two goals • That all service classes must meet their QoS requirements • The scheduling schemes must achieve efficiency and fairness among all service classes [4] Pahalawatta, P.; Berry, R.; Pappas, T.; Katsaggelos, A. “Content-Aware Resource Allocation and Packet Scheduling for Video Transmission over Wireless Networks,” IEEE Journal on Selected Areas in Communications, Volume 25, Issue 4, Page(s):749 – 759, May 2007. [5] Lera, A.; Molinaro, A.; Pizzi, S. “Channel-Aware Scheduling for QoS and Fairness Provisioning in IEEE 802.16/WiMAX Broadband Wireless Access Systems,” IEEE Network, Volume 21, Issue 5, Page(s):34 – 41, Sept.-Oct. 2007.
Introduction • To achieve these goals, related scheduling schemes have been proposed • Deficit Fair Priority Queue (DFPQ) [7] • Preemptive Deficit Fair Priority Queue (PDFPQ) [8] [7] Jianfeng Chen, Wenhua Jiao, Hongxi Wang, “A Service Flow Management Strategy for IEEE 802.16 Broadband Wireless Access Systems in TDD Mode,” ICC 2005, Page(s): 3422-3426, 16-20 May 2005. [8] Safa, Haidar; Artail, Hassan; Karam, Marcel; Soudah, Rawan; Khayat, Samar; “New Scheduling Architecture for IEEE 802.16 Wireless Metropolitan Area Network,” IEEE/ACS International Conference on Computer Systems and Applications, 2007, Page(s): 203-210, 13-16 May 2007.
Introduction • To propose an enhanced scheduling scheme called Adaptive Deficit Priority Queue (ADPQ) • To guarantee the delay of rtPS • To protect lower priority service classes from starvation
Background • Point-to-Multipoint network topology
Background • Point-to-Multipoint network topology • Downlink DL-MAP BS SS SS SS
Background • Point-to-Multipoint network topology • Uplink UL-MAP BS SS SS SS
Background • IEEE 802.16 standard defines four kinds of service classes • Unsolicited Grant Service (UGS) • Real-Time Polling Service (rtPS) • Non-Real-Time Polling Service (nrtPS) • Best Effort Service (BE) • The standard does not recommend any particular scheme in detail
Background • Unsolicited Grant Service (UGS) • Voice over IP (VoIP) Resource Time
Background • Real-Time Polling Service (rtPS) • Video streaming Resource Time
Background • Non-Real-Time Polling Service (nrtPS) • guarantees the minimum bandwidth and the longest delay tolerance range. nrtPS also uses polling to request bandwidth, but nrtPS is polled using a longer polling interval than rtPS • FTP • Best Effort Service (BE) • no QoS requirements • contention-based bandwidth request • HTTP
Related works • QoS architectures
Related works • Deficit Fair Priority Queue (DFPQ) • Definition:Deficit Counter (DC) DC[rtPS] 800 DC[nrtPS] 500 DC[BE] 300
Related works • Deficit Fair Priority Queue (DFPQ) Classifier rtPS nrtPS BE 300 100 100 250 300 500 200 400 250 350 DC[rtPS] 800 DC[nrtPS] 500 DC[BE] 300 Scheduler
Related works • Deficit Fair Priority Queue (DFPQ) Classifier rtPS nrtPS BE 300 100 100 250 300 500 200 400 250 350 DC[rtPS] 800 DC[rtPS] 0 DC[nrtPS] 500 DC[BE] 300 Scheduler
Related works • Deficit Fair Priority Queue (DFPQ) Classifier rtPS nrtPS BE 300 100 250 500 200 250 350 DC[rtPS] 0 DC[nrtPS] -250 DC[nrtPS] 500 DC[BE] 300 Scheduler
Related works • Preemptive Deficit Fair Priority Queue (PDFPQ) Classifier deadline Qcrit=320 rtPS nrtPS BE 450 300 300 100 100 250 Q[rtPS]*0.4 250 300 500 200 120 400 250 350 DC[rtPS] 800 DC[nrtPS] 500 DC[BE] 300 Scheduler
Related works • Preemptive Deficit Fair Priority Queue (PDFPQ) remaining deficit counter of service class which is serviced at that time packet length of rtPS packet available capacity in the current frame
ADPQ Proposed adaptive deficit priority queue scheme
Proposed adaptive deficit priority queue (ADPQ) scheme current time rtPS maximum latency parameter frame duration the arrival time of packet quantum (byte)
Proposed adaptive deficit priority queue (ADPQ) scheme Tf = 100 ms Tnow = 500 ms Tlatency = 300 ms Q[rtPS] = 800 DC[rtPS] = 800 rtPS 300 100 300 400 390ms 350ms 210ms 120ms Enqueue time Q[nrtPS] = 500 DC[nrtPS] = 500 nrtPS 100 500 250 Q[BE] = 300 DC[BE] = 300 BE 250 200 350
Proposed adaptive deficit priority queue (ADPQ) scheme Tf = 100 ms Tnow = 500 ms Tlatency = 300 ms Q[rtPS] = 800 DC[rtPS] = 800 rtPS 300 100 300 400 390ms 350ms 210ms 120ms Enqueue time Q[nrtPS] = 500 DC[nrtPS] = 500 100 + 500 – 210 = 390 > 300 rtPS.threshold nrtPS 100 + 500 – 120 = 480 > 300 100 500 250 Q[BE] = 300 DC[BE] = 300 800 + 300 + 400 = 1500 BE 250 200 350
Proposed adaptive deficit priority queue (ADPQ) scheme Tf = 100 ms Tnow = 500 ms Tlatency = 300 ms Q[rtPS] = 800 DC[rtPS] = 1500 rtPS 300 100 300 400 390ms 350ms 210ms 120ms Enqueue time Q[nrtPS] = 500 DC[nrtPS] = 500 nrtPS 100 500 250 Q[BE] = 300 DC[BE] = 300 BE 250 200 350
Proposed adaptive deficit priority queue (ADPQ) scheme Tf = 100 ms Tnow = 500 ms Tlatency = 300 ms Q[rtPS] = 800 DC[rtPS] = 1500 rtPS 300 100 300 400 390ms 350ms 210ms 120ms Enqueue time Q[nrtPS] = 500 DC[nrtPS] = 500 nrtPS 100 500 250 Q[BE] = 300 DC[BE] = 300 BE 250 200 350
Proposed adaptive deficit priority queue (ADPQ) scheme Tf = 100 ms Tnow = 500 ms Tlatency = 300 ms Q[rtPS] = 800 DC[rtPS] = 400 rtPS Enqueue time Q[nrtPS] = 500 DC[nrtPS] = 500 nrtPS 100 500 250 Q[BE] = 300 DC[BE] = 300 BE 250 200 350
Proposed adaptive deficit priority queue (ADPQ) scheme Tf = 100 ms Tnow = 500 ms Tlatency = 300 ms Q[rtPS] = 800 DC[rtPS] = 400 rtPS Enqueue time Q[nrtPS] = 500 DC[nrtPS] = -250 nrtPS 100 Q[BE] = 300 DC[BE] = 300 BE 250 200 350
Proposed adaptive deficit priority queue (ADPQ) scheme Tf = 100 ms Tnow = 500 ms Tlatency = 300 ms Q[rtPS] = 800 DC[rtPS] = 400 rtPS Enqueue time Q[nrtPS] = 500 DC[nrtPS] = -250 nrtPS 100 Q[BE] = 300 DC[BE] = -50 BE 250 200
Simulation • rtPS
Simulation • nrtPS
Simulation • BE
Conclusion • The uplink scheduling scheme can enhance the performance of rtPS traffic and avoids starvation of low priority service classes • If packets may expire in the next frame, the scheduler transmits these packets in the current frame • ADPQ is a more efficient scheduling scheme for the transmission of delay-sensitive applications than DFPQ and PDFPQ