MAC and QoS in WiMAX Mesh Networks
A Worldwide Interoperability for Microwave Access (WiMAX) network utilizes a shared medium to provide efficient transmission services. Scheduling services represent the data handling mechanisms supported by the media access control (MAC) scheduler for data transport on a connection. The mandatory quality of service (QoS) service flow parameters for this scheduling service are maximum sustained traffic rate, maximum latency, tolerated jitter, and request/transmission policy. The chapter reviews the services and mechanisms to provide the QoS specified by the MAC layer protocol in the point-to-multipoin topology of WiMAX systems. The non-real-time polling service offers unicast polls on a regular basis, which ensures that the service flow receives request opportunities, even during network congestion. The mandatory contention resolution method is the truncated binary exponential back-off, with the initial back-off window and the maximum back-off window controlled by the base station.