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The QoS of WiMAX. Outline. Introduction Connections & Service flows Classifier & Scheduler Scheduling services Handover. Introduction. QoS supporting is a fundamental part of the WiMAX MAC-layer design. How does WiMAX support for QoS?. Connections.
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Outline • Introduction • Connections & Service flows • Classifier & Scheduler • Scheduling services • Handover
Introduction • QoS supporting is a fundamental part of the WiMAX MAC-layer design. • How does WiMAX support for QoS?
Connections • A connection-oriented MAC architecture • all downlink and uplink connections are controlled by the serving BS • Each connection is identified by a connection identifier (CID)
Service flows • A service flow is a unidirectional flow of packets • with a particular set of QoS parameters • is identified by a service flow identifier (SFID) • The service flow characteristics of the connection provide the QoS for that packet
DSD DSC NULL DSA OPERATIONAL Service Flow Management • Dynamic Service Change (DSC) • Dynamic Service Delete (DSD) • Dynamic Service Activate (DSA)
Classifier • A classifier is a set of matching criteria applied to each packet. It consists of • some protocol-specific packet matching criteria (destination IP address, for example) • a classifier priority • a reference to a CID • Classifiers can be added by dynamic signaling
Quality of Service Support 1.Associate packets into service flow 2.Define QoS parameter for each service flow 3.Dynamically establishing QoS-enabled service flows 4.Associate QoS service flow with logical connections
Scheduling services • Four services are supported in 802.16 802.16-2004 • Unsolicited Grant Service (UGS), • Real-time Polling Service (rtPS), • Non-real-time Polling Service (nrtPS), and • Best Effort (BE). • Five services are supported in 802.16e 802.16e-2005 • UGS (Unsolicited Grant Service) • RT-VR (Real-Time -Variable Rate Service) • NRT-VR (Non-Real Time -Variable Rate service) • BE (Best Efforts) • ERT-VR (Extended Real-Time Variable Rate)
Unsolicited Grant Service (UGS) • support real-time data streams consisting of fixed-size data packets issued at periodic intervals • Such as T1/E1 and Voice over IP without silence suppression INTERNET VoIP
Real-time Polling Service (rtPS) • support real-time data streams consisting of variable-sized data packets that are issued at periodic intervals • Such as moving pictures experts group (MPEG) video.
Non-real-time Polling Service (nrtPS) • support delay-tolerant data streams consisting of variable-sized data packets for which a minimum data rate is required • such as FTP
Best Effort (BE) • support data streams for which no minimum service level is required and therefore may be handled on a space-available basis.
Extended Real-Time Variable Rate (ERT-VR) service • support real-time applications with variable data-rates, which require guaranteed data and delay, for example VoIP with silence suppression.
Handover • An mobile station (MS) migrates from the air-interface provided by one BS to the air interface provided by another BS
Handover in WiMAX • Hard Handover • Fast Base Station Switching (FBSS) • Active Set (Diversity set) • Anchor BS • MS Anchor BS • Macro Diversity Handover (MDHO) • Active Set (Diversity set) • Anchor BS • MS all BSs in an active set