Modelling CAC and Scheduling in IEEE 802'16 Networks for QoS Analysis

1
Modelling CAC and Scheduling in IEEE 802.16
Networks for QoS Analysis
Pieter Kritzinger
Giuseppe Iazeolla
Paolo Pileggi
ppileggi_at_cs.uct.ac.za
psk_at_cs.uct.ac.za
iazeolla_at_info.uniroma2.it
2
Application Scenario

• Wireless Internet
• 802.16-2004 backhaul
• (Fixed WiMAX)
• QoS support?

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QoS Support?
802.16-2004 Four Scheduling services Traffic
Categories (TC)

• Unsolicited Grant Service (UGS) VoIP
• Real-time Polling Service (rtPS) MPEG Streaming
  video
• Non-real-time Polling Service (nrtPS) FTP
• Best Effort (BE) HTTP

4
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.

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Modelling CAC and SCHED

• Roles?
• Relationships?
• Impact on network performance?
• Operational Modes?
• Granting Paradigms?
• Performance Model?
• QoS Measures?

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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

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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

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Admission Control (AC) Modes

• PMP-GPC
• PMP-GPSS
• MSH-GPC
• MSH-GPSS

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Two-Tier Hierarchical Hybrid Performance Model
(HHPM)
Hierarchical Model

• T1 Simulator
• with component interfaces

T2 Components simulation or analytic
Hybrid Model a combination of both analytic
procedure and simulation
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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.
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System Performance Model (SPM)

• SPM
• BS Machine Model (MM)
• SS Workload Model(WLM)

• BS/SS Framework
• Architectures

Network of Queues (NoQ) Model
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Tier 1 Simulator

• 4 interfaces
• CAC
• SCHED
• TRANSM
• WLM

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Tier 2 CAC

• AdmissionController interface

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Tier 2 SCHED

• Scheduling interface
• DLService interface

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Tier 2 WLM

• WorkloadGeneration interface

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QoS Analysis
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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

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?
http//www.cs.uct.ac.za/ppileggi/ http//www.cs.u
ct.ac.za/psk/ http//www.cs.uct.ac.za/Research/DN
A/ http//www.sel.uniroma2.it/iazeolla/ http//www
.disp.uniroma2.it/jml/