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Modelling CAC and Scheduling in IEEE 802.16 Networks for QoS Analysis. Paolo Pileggi. Pieter Kritzinger. Giuseppe Iazeolla. psk@cs.uct.ac.za. ppileggi@cs.uct.ac.za. iazeolla@info.uniroma2.it. Application Scenario. Wireless Internet 802.16-2004 backhaul ( Fixed WiMAX ) QoS support?.
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Modelling CAC and Scheduling in IEEE 802.16 Networks for QoS Analysis Paolo Pileggi Pieter Kritzinger Giuseppe Iazeolla psk@cs.uct.ac.za ppileggi@cs.uct.ac.za iazeolla@info.uniroma2.it
Application Scenario • Wireless Internet • 802.16-2004 backhaul (Fixed WiMAX) • QoS support?
QoS Support? 802.16-2004 Four Scheduling services Traffic Categories (TC) • Unsolicited Grant Service (UGS): VoIP • Real-time Polling Service (rtPS): MPEGStreaming video • Non-real-time Polling Service (nrtPS): FTP • Best Effort (BE): HTTP
QoS Support? • Connection Admission Control (CAC) • Connection-oriented • Left unspecified by the standard … • Scheduling (SCHED) • Left unspecified by the standard … … allowing implementers to create market and performance advantages.
Modelling CAC and SCHED • Roles? • Relationships? • Impact on network performance? • Operational Modes? • Granting Paradigms? • Performance Model? • QoS Measures?
Modes of Operation • MeSH (MSH) • Multi-hop • BS ↔ SSneighbour N • SSneighbour N ↔ SSneighbour N-1 Point-to-MultiPoint (PMP) • One-hop • BS ↔ SSn & SSn-1 (!↔) SSn
Granting Paradigms Grant-Per-Connection (GPC) • Request made by SS for individual connections • SS only needs forward data for connections during certain time slots • Grant-Per-SS (GPSS) • Request made by SS for an aggregation of connections • SS responsible to share the resource grant amongst connections belonging to a granted aggregated request
Admission Control (AC) Modes PMP-GPC PMP-GPSS MSH-GPC MSH-GPSS
Two-Tier Hierarchical Hybrid Performance Model (HHPM) T1 Simulator with component interfaces Hierarchical Model T2 Components simulation or analytic Hybrid Model a combination of both analytic procedure and simulation
Analytical Frameworkfor SCHED and CAC • Roles of … • Relationships between … • Position in protocol stack • Data Flow • BS and SS model architectures Suited to all AC Modes Iazeolla, G., Kritzinger, P. and Pileggi, P. Modelling Quality of Service in IEEE 802.16 Networks. 16th International Conference on Software, Telecommunications and Computer Networks (SoftCOM'08). September 25 - 27, 2008. Split - Dubrovnik, Croatia.
System Performance Model (SPM) SPM • BS: Machine Model (MM) • SS: Workload Model(WLM) BS/SS Framework Architectures Network of Queues (NoQ) Model
Tier 1 Simulator 4 interfaces • CAC • SCHED • TRANSM • WLM
Tier 2 CAC • AdmissionController interface
Tier 2 SCHED • Scheduling interface • DLService interface
Tier 2 WLM • WorkloadGeneration interface
Future work • Other AC modes • Routing Interface: cross-layer design • Buffer Management Schemes • Vertical hand-off: Achieving End-to-end QoS • Traffic Mapping between 802.11e and 802.16
? http://www.cs.uct.ac.za/~ppileggi/ http://www.cs.uct.ac.za/~psk/ http://www.cs.uct.ac.za/Research/DNA/ http://www.sel.uniroma2.it/iazeolla/ http://www.disp.uniroma2.it/jml/