Wireless broadband access: WiMAX and beyond - Investigation of bandwidth request mechanisms under point-to-multipoint mode of WiMAX networks

The WiMAX standard specifies a metropolitan area broadband wireless access air interface. In order to support QoS for multimedia applications, various bandwidth request and scheduling mechanisms are suggested in WiMAX, in which a subscriber station can send request messages to a base station, and the base station can grant or reject the request according to the available radio resources. This article first compares two fundamental bandwidth request mechanisms specified in the standard, random access vs. polling under the point-to-multipoint mode, a mandatory transmission mode. Our results demonstrate that random access outperforms polling when the request rate is low. However, its performance degrades significantly when the channel is congested. Adaptive switching between random access and polling according to load can improve system performance. We also investigate the impact of channel noise on the random access request mechanism

Connection admission control and packet scheduling for IEEE 802.16 networks

Includes bibliographical references.The IEEE 802.16 standard introduced as one of the Wireless Metropolitan Area Networks (WMAN) for Broadband Wireless Access (BWA) which is known as Worldwide Interoperability for Microwave Access (WiMAX), provides a solution of broadband connectivity to areas where wired infrastructure is economically and technically infeasible. Apart from the advantage of having high speeds and low costs, IEEE 802.16 has the capability to simultaneously support various service types with required QoS characteristics. ... While IEEE 802.16 standard defines medium access control (MAC) and physical (PHY) layers specification, admission control and packet scheduling mechanisms which are important elements of QoS provisioning are left to vendors to design and implement for service differentiation and QoS support

USING THE CONCEPT OF A MAC SCHEDULING ALGORITHM FOR WIMAX NETWORKING ARCHITECTURE

Wimax is wireless digital communication system which is intended for wireless Metropolitan area networks. Wimax standsfor worldwide interoperability for microwave access. Wimax Technology enables ubiquitous delivery of wireless broadbandservice for fixed and or mobile users. An IEEE 802.16 wireless system can provide broadband wireless access to subscriberstations and operate in mesh mode. The communication between a subscriber station and a base station can pass through oneor more intermediate subscriber stations. The IEEE 802.16 standard provides a centralized scheduling mechanism thatsupports contention-free and resource-guarantee transmission services in mesh mode. This paper show how MAC schedulingarchitecture is emphasized for IEEE 802.16 standards.Keywords: MAC, QoS class scheduling, IEEE 802.16, WiMax, Network

A Novel QoS Guarantee Mechanism in IEEE 802.16 Mesh Networks

IEEE 802.16 defines perfect QoS (Quality of Service) guarantee mechanism in PMP (Point to Multi-Point) mode and denotes mesh mode cannot provide this capability. To resolve this problem of WiMAX Mesh network, a novel QoS guarantee mechanism including protocol process and minislot allocation algorithm is proposed. This mechanism uses existing service classes in original standard. Protocol processes that manage dynamic service flow are defined. WiMAX MAC layer is re-designed to support service classification in mesh mode. Using extended distributed scheduling messages, the delivery method of dynamic service management messages in WiMAX mesh networks is implemented. Minislot allocation algorithm is given to support data scheduling of various services. Service establishment time is analyzed in this paper. The simulation result shows that the mechanism can provide QoS in WiMAX mesh networks effectively