the qos of wimax
DESCRIPTION
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. - PowerPoint PPT PresentationTRANSCRIPT
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
• 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)
• 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
Service flows
Operation Object Model
Service Flow Creation
Service Flow Management
• Dynamic Service Change (DSC)
• Dynamic Service Delete (DSD)
• Dynamic Service Activate (DSA)
NULL
OPERATIONAL
DSD
DSA
DSC
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 flow2.Define QoS parameter for each service flow3.Dynamically establishing QoS-enabled service flows4.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