During the last few years, users all over the world have become more and more accustomed to the availability of broadband access. This has boosted the use of a wide variety both of established and recent multimedia applications. However, there are cases where it is too expensive for network providers to serve a community of users. This is typically the case in rural and suburban areas, where there is slow deployment (or no deployment at all) of traditional wired technologies for broadband access (e.g., cable modems, xDSL). In those cases, the most promising opportunity rests with Broadband Wireless Access technologies, such as the IEEE 802.16, also known as WiMAX. One of the features of the MAC layer of 802.16 is that it is designed to differentiate service among traffic categories with different multimedia requirements. This article focuses on mechanisms that are available in an 802.16 system to support quality of service (QoS) and whose effectiveness is evaluated through simulation

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Abstract-In wireless mesh networks, the end-to-end throughput of traffic flows depends on the path length, i.e. the higher the number of hops, the lower becomes the throughput. In this paper, a Fair End-to-end Bandwidth Allocation (FEBA) algorithm is introduced to solve this problem. FEBA is implemented at the Medium Access Control (MAC) layer of single-radio, multiple channels IEEE 802.16 mesh nodes, operated in a distributed coordinated scheduling mode. FEBA negotiates bandwidth among neighbors to assign a fair share to each end-to-end traffic flow. This is carried out in two steps. First, bandwidth is requested and granted in a round-robin fashion where heavily loaded links are provided with a proportionally higher amount of service than the lightly loaded links at each round. Second, at each output link, packets from different traffic flows are buffered in separate queues which are served by the Deficit Round Robin (DRR) scheduling algorithm. If multiple channels are available, all of them are shared evenly in order to increase the network capacity due to frequency reuse. The performance of FEBA is evaluated by extensive simulations and is shown to provide fairness by balancing the bandwidth among traffic flows.

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