WIMAX Basics From PHY Layer to Scheduling And Multicasting Approaches

WiMAX (Worldwide Interoperability for Microwave Access) is an emerging broadband wirelesstechnology for providing Last mile solutions for supporting higher bandwidth and multiple serviceclasses with various quality of service requirement. The unique architecture of the WiMAX MAC andPHY layers that uses OFDMA to allocate multiple channels with different modulation schema andmultiple time slots for each channel allows better adaptation of heterogeneous user’s requirements. Themain architecture in WiMAX uses PMP (Point to Multipoint), Mesh mode or the new MMR (Mobile Multihop Mode) deployments where scheduling and multicasting have different approaches. In PMP SS(Subscriber Station) connects directly to BS (Base Station) in a single hop route so channel conditionsadaptations and supporting QoS for classes of services is the key points in scheduling, admission controlor multicasting, while in Mesh networks SS connects to other SS Stations or to the BS in a multi hoproutes, the MMR mode extends the PMP mode in which the SS connects to either a relay station (RS) orto Bs. Both MMR and Mesh uses centralized or distributed scheduling with multicasting schemas basedon scheduling trees for routing. In this paper a broad study is conducted About WiMAX technology PMPand Mesh deployments from main physical layers features with differentiation of MAC layer features toscheduling and multicasting approaches in both modes of operations.