1. The QoS of WiMAX

2. Outline Introduction Connections & Service flows Classifier & Scheduler Scheduling services Handover

3. Introduction QoS supporting is a fundamental part of the WiMAX MAC-layer design. How does WiMAX support for QoS?

4. 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)

5. 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

6. Operation Object Model

7. Service Flow Creation

8. Service Flow Management Dynamic Service Change (DSC) Dynamic Service Delete (DSD) Dynamic Service Activate (DSA) NULL OPERATIONAL DSD DSA DSC

9. 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

10. 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

11. 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)

12. 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

13. 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.

14. 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

15. Best Effort (BE) support data streams for which no minimum service level is required and therefore may be handled on a space-available basis.

16. 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.

17. Handover An mobile station (MS) migrates from the air- interface provided by one BS to the air interface provided by another BS

18. 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